Demonology is the highest DPS in all DS HC Bosses at the moment (ref: worldoflogs), thus in current High End PVE , we stil have a unforgiving spec, which needs you to be a Melee Range Caster to make proper Damage, have the right Pet out (even if the situation in RNG driven). Manage zillion DoTs, Debuffs, Buffs, and CDs - VERY unforgivingly.
Let's start with facts:
- demo parses are lowest on Morchok;
- not the highest on Zonozz (furthermore, the two top demo logs have damage done only to Zonozz and Claw - whether you consider such logs relevant or not is up to you. Demo is the worst spec for progress here);
- the top demo parse for Warmaster is 5k DPS above the other demo parses, I couldn't find what exactly he did but I'd ignore that parse. Affliction is pretty much tailored for this boss and is the best spec here, I'd argue demo is the worst here;
- there are 23 100k+ DPS parses for affliction, and 0 for demo on Madness.
If I was you, though, I'd never trust world of logs top parses. People abuse a lot just to find ways to be on top there. The top 5 parses are always in some way abused - it's not exactly hard when you're in a high ranked guild and farming this content with ease.
If you still want to look at statistics, just use this: http://raidbots.com/dpsbot/Overall_DPS/25H/100/14/60/default/#1o
This parses the logs on WoL and builds graphs. Top 100 for the last 2 months, by default. (Don't be mad at me if I'm being captain obvious here and you already knew.)
So, realistically there's only three bosses where demonology is the best spec: Ultraxion, Yorsahj and Spine. And I wouldn't even trust any of this data for Spine, just too easy to AoE adds - affliction actually beats demo at this, as shown by the #1 log from WoL.
I fully agree with you that demonology is a very clunky spec while at the same time being very unforgiving. That's on top of just being unnecessarily complex (e.g. pet twisting, moonwell chalice last tier, stuff like that). It suffers way too much from movement and target switches, and its AoE relies on having cooldowns up - the same cooldowns that you rely heavily on for single target damage. It has the longest ramp up time of all specs and a spell with melee range requirement. It basically requires a Patchwerk fight to be able to use all of its potential, even in theory, and the only reason its topping on Yorsahj is getting lucky with adds syncing with cooldowns.
But what makes you think that demonology is our "highest DPS spec" and its mandatory to run it is beyond me. The class isn't broken - demonology is. Our specs are really balanced when it comes to raw output (look at top Ultraxion parses - this is one of the rare cases where it makes sense to compare top parses), so if you don't like demonology mechanics and how it works on DS bosses, just don't play it. The other two specs have pretty fluent and much more comfortable playstyles.
Regarding those "things":
- if you don't notice your pet dying, it's your fault;
- just give DI to the SP no matter what;
- if you can't talk on vent, that's your problem - any class with a battle res experiences the same issue if they type;
- the raid usually doesn't wait for elemental shaman totems or army of the dead too, we're not alone in this.