1. Ability to drop banner to create a checkpoint, that you might return after forced respawn. Also when a player teleports on you they will teleport on your banner. Also the teleporting from banner, should be disabled for players who are in the brawl area.
2. Respawn timer is capped at 60 seconds on multiple death occasions, so you don't dive into the fray when your spells are on cooldown, regarding the #1. Respawn counter will be longer because pinning a banner close to champs means you'll farm somehow faster.
3. More death penalty when Nephalem Valor is active. 1 point of vitality effectiveness loss on forced respawn which will cause 3% of total life lost roughly. Vitality effectiveness currently capped at 35 hp per vitality, and I think it's manageable for it to drop down to 10 hp per vitality minimum. Avoidable if another team member resurrects you on the point. Can be wiped away when player resets the whole Nephalem Valor. If you're a glass-cannon or too bulky you better play in parties where you can fit in.
4. As Monster Power public games introduced, same-class but different gender characters should increase each other's source generation by 10%. So people are meant to play multiplayer, even more regarding the #3 and #5. Else, this bonus should be added to certain passive abilities but this simply holding the hand of player which I wouldn't like to see.
5. With every high Paragon Level (75 and above) friend to join your game, whole party gets one free Nephalem stack. Since there are 4 possible max players, 3 invite joined players will grant 3 Nephalem Valor buff to the whole party. Cutting the time to do a boss rush. So higher Paragon Level players will play party games instead of brawling all the time.
6. At the case of Brawling or PvP, higher Paragon Level might cause you to drop more gold when slain, as you advance. If you're a higher Paragon you should be tough anyway, otherwise don't brawl at all.
System changes and artifacts
1. Charms should make a return with Talisman artifact, to take place of scrapped skill tree system. Talisman was in the beta stages of the game then removed, planned to be rewarded to hero after a quest. I assume that was the talisman of the Leah given by her mother, then she rewards it to us. Every time we repeat that quest at higher difficulties Talisman should upgrade to carry more charm units in it. Single charm unit at Normal, 5 charm units at Nightmare, 9 charm units at Hell and finally 13 charm units at Inferno. Charms only should offer static random rolled stat bonuses such as +6 to Strength or +9 to Intelligence or even +# static damage bonus to specific class skill (such as static damage modifier to some skill; think them as skill points) , they should only carry a single property on them. Unique account bound ones could provide more properties or may be even charged skills on them.
2. Quick Item slot, with the hotkey "E". And by the single flick of mousewheel and hitting "W" button character should swap the weapons with some delay. Item slot shouldn't get affect from elective mode or primary, secondary slots and act like health potion slot. Quick Slot should allow player to use an Enchanted Scroll, a charged skill, throw a potion. I remember spellbooks at Diablo1, how about teaching to your character new spells too? Charged spells can be classified with their cast source cost; some may require mana, others discipline, spirit and so on, to maintain balance. Some may require no cost but comes with a very long cooldown.
3. Bring back CC effects on elemental damage of weapons, they should only occur by luck on critical hits, and their proc chance should be penalized as difficulty rises. Such as 20% as default chance on Normal and 12% at Nightmare difficulties, then it drops down to 8% at Hell and 4% at Inferno difficulties. For example Lightning damage should knockback, Cold damage should snare, Holy damage should blind, Fire damage should fear, Poison damage should confuse and Arcane damage should immobilize enemies. Since they only occur on critical hits, their chance is approximately around 1,5% at Inferno for an average 30% crit chance player. So no CC gear will be trashed at all, since the CC effects will be based upon weapon damage bonus. If you read further I put more on the elite CC resistances.
Skills and stats
1. Passive skills need work, they should rely on stat and attribute comparisons and grant bonuses to the player if requirements meet. For example; "If your strength is higher than your dexterity, Cold Blooded grants 50% more critical hit damage against frozen targets" "If your Lightning Resistance is highest of your resistances Sixth Sense also adds 10% bonus dodge chance", "If your dexterity is 120% or higher of your strength, Weapons Master allows you to dual wield two-handed swords, maces and axes". That will create a constant item circulation among classes, and will create build diversity sooner or later.
Some passive skills can be turned to be "ranked" for character customization, like the planned trait system before D3 goes live. Rank system could require Paragon Levels as I've been insisting.
2. Stats should benefit more than just a single benefit as a second stat. They should offer extra benefits, so this way most of the bad rolled items will be saved from being trashes and good rolled items will have a price increase. If secondary stats would give more benefits everyone would find one that fits their character. Such example; Strength could increase movement speed passively as it increases the armor with 1:1 rate, Dexterity could grant faster hit recovery as it increases the dodge chance, Intelligence could reduce the crowd control duration that you are under as it increases the resistances with 10:1 rate. All of these details can be bound to ranked passive skills I've once mentioned.
3. With drop rates are being nerfed and stat range being buffed. I think Nephalem Valor buff should change. Like instead of offering Magic Find and Gold Find, it can offer +%2 life bonus(to compensate with new vit effectiveness death penalty I mentioned) and +%2 damage to elite per stack; %15 experience bonus should stay thou.
1. Blacksmith should gain an ability to open a socket to any blue magical quality gear, as you level him up. Socketed magical belts, shoulders, bracer... Because that will help Magical items to have a degree of quality compared to rare quality items, and crafting will have a meaning. As I will mention at #2 and #3 that will create build diversity and customization.
2. Jewelcrafter should create actual jewels regarding to the recipes with random properties. Such example; "Journeyman Jewel of the Bear" should always roll +[30-45] vitality with 2 random prefixes and level requirement of 22, "Grandmaster Jewel of the Pain" should always roll +[40-55] dexterity with 3 random prefixes and level requirement of 46. Hope you get the idea, jewel recipes are based on the proficiency and the suffix of the jewel. Also crafting a jewel should require high tier gems and possibly brimstones, in return they offer chance of rolling powerful affixes such as slightly increased attack speed of 1-2%, so player can use that jewel recipes as a gem and item sink.
3. Mystic Artisan, makes a return she will craft and upgrade runes, showing different kinds of masteries. Arcane Arts Tab (Upgrading runes -require dyes, essences, tomes- and exchanges skill runes through divine knowledge), Alchemy Tab (Creates powerful concoctions such as Throwing Oil and Rancid Gas Potions, Rejuvenation Potion, Thawing and Antidote Potions and stat boosting Elixirs(+20 vita for 15 seconds, +100 int for 20 seconds)), Enchant Tab (attribute boosting Enchanted Scrolls (+200 LoH for 30 sec, +50% Crit Damage for 10 sec... etc.), charging skill staffs), Trade Tab (selling random charms, random elixirs, random scrolls, random charged staffs)
4. Rune system should return with runewords. Complicated and powerful runewords should require more sockets, and their benefits should be unique but less. Runes should take place of Mystic's item enchant ability at beta stage, for example Um Rune related to Obsidian glyph, requiring Paragon Level 42, rolls "[20-40]% chance of cause bleeding for [#-#] damage over 5 seconds" on weapons. The damage range should be completely random. Player can roll 105-2258 damage or 228-780 damage. It will have a random roll every time you remove the socket and combine it again.
Runes should NEVER offer straight static bonuses like +10 vita, or +10 int, they either should offer bonuses based on percentage. Such bonuses as; % less damage from elites/ranged/melee, % more damage to the elites, life%, class skill bonus, % attack speed, % elemental damage,% chance to CC...
Runewords only should work on socketed magical quality items, and they should offer extra affixes when completed. That's why Blacksmith should open socket to only magical items.
5. Rune glyphs should appear like the scrapped system; Alabaster, Indigo, Golden, Crimson, Obsidian. Blacksmith should craft them once with a plan. To upgrade runes you should bring glyphs to the Mystic, along with the required essences and special dyes, they may act like keys in your talisman to trigger runewords from the runes you carry on your gear.
6. May be Artisans may need apprentices as they level up? Haedrig takes Kormac for he cannot find the inspire to write love letters to Karyna and Kormac takes the job of improving the max durability of armors; Covetous Shen takes Scoundrel for he rips the townsfolk off from their precious items through gambling, he will take the job of the gambler to sell unidentified items to the player; Mystic would take the Enchantress perhaps for she can craft successful enchanted scrolls like her name suggests.