All of them should be able to autocast. I want to take part of the fights as a dragon, and I won't have any time for micro-managing (which I don't like much anyway).
This. I am fine with the autocast being crappy. But if I have two fights at the same time to manage and warlocks with meet the beetles then I have to pick which fight I use that ability in (or sacrifice being a dragon to manage the abilities of two fight simultaneously and then probably do a worse job then the autocasts as my attention would be too split.)
Conversely if I have autocast I could leave one group on autocast while manually triggering the abilities in the fight that I want to participate. Sure the group on autocast would probably hit a couple of troopers and a hunter if they are lucky while ignoring the armor behind them but that's still better than the nothing that they do in the current build.
That example is only with one ability too. Once you reach late game when units have tons of targetable abilities I find I can't even go into the dragon at all. All of my time has to be spent managing unit abilities and if I ever get into two fights at once one of my groups is gonna die. Since the Dragon has a TON of abilities and the whole point of the game is to play as a dragon using your abilities to turn the tide, not being able to actually use dragon mode as you have to spend all of your time microing abilities is a real drag.
I get that some players are REALLY fast clickers who are used to games like SC2 and those players can manual target everything (autocast is usually toggle-able) but for those of us that prefer a more relaxing pace and don't have ungodly clicking skills the current setup is near impossible to keep up in late game. Abilites will still be better used by humans manual targeting but this will allow the less e-sports orientated crowd to actually play the game using autocast for some groups/abilites.