I want to do the other acts; it would really make it feel more like time well spent. However, I would argue that you would get roughly 4 times more gold and legendaries by only doing the end of Act 3, given the high density.
There's not much enjoyment. The farming run is between 15 and 30 minutes, which makes it extremely repetitive. If monster density throughout the game was even, then a farming run would be a good couple of hours, and although that would eventually become boring too, it would be fifty times more enjoyable!
Yhihi you have to understand the sort of speeds and quantity of slaughter we are dealing with. A DH guy I know farms act 3 with me, we play an extended Alk run and were killing maybe 80% of act 3 in 25 minutes or so. Its only when you do it you realise ok, doing these runs theres rarely a moment where there isnt a monster on my screen, and in fact the vast majority of the run is spent with upwards of 10, 20, 30 creatures on screen being obliterated. Were not even great Demon Hunters, mid tier at best.
Demon Hunters use Vengeance to gain hatred + disc from health globes, barbs gain fury from crits through Into The Fray, wizards in Archon get their timer ticked back every time they kill, WDs gain mana from globes... the more they kill the more resources they generate to kill even more, new builds become viable that feed of death and become this rolling wave of destruction, suddenly youre smashing through 15 monsters in a second without breaking step, and you need to in order to maintain this sort of assault.
Then you go back to act 1 where you are too resource starved to use these crazy builds, run down an empty corridor, find 3 dudes praying, they get killed, walk through an empty room, down another empty corridor and youre thinking 'if this was act 3 Id have killed 2 elite packs and 60 monsters in the time Ive just spent spamming move speed skills looking for a fight'. Don't get me wrong I do it, but I shouldnt have to do it because Im bored of act 3, I should be able to do it because its fun and rewarding, its just not, high carnage builds arnt as viable, you waste a ton of resources sprinting/valuting between fights. Blizzard said it themselves many times, Diablo is at its best when you are smashing hordes of critters.
Its not for everyone, I hated act 3 as well, Im just saying when you get to 12k elite kills and you are wondering why you arnt that guy whos picking up a million gold a day and listing 10 auctions for 5 to 60 million gold each, why people on youtube are using these insane builds to hammer down foes that seem like a different game to the one youre playing youll check it out. Then 4 weeks later youll have 25k elite kills and 150kdps.