TL;DR: These classes are the best designed and well balanced in all aspects compared to the unlisted classes as starting bases for companions, but don't let me tell you how to play cause I'm not trying to nor do I want to. You spent your money you play how you want.
Fighter, Knight, Enchanter, Rogue, Ranger, Wizard and Shadowblade.
These only apply to companions since you can customize your main character completely, but companions are stuck with the base classes talents, stats, etc.
You can beat Act 1 as anything sure and probably the whole game, it'll just take more time, more planning and more frustration playing as classes that are underwhelming like Inquisitor or Wayfarer, but if you want to play effectively with minimal frustration you need to take these classes as bases for your companions otherwise you are only gimping your party with classes that bring nothing that a better designed one could and extra with it.
Obviously i'm no authority on it and I'm not claiming that these classes are the only way to play, cause that isn't true. I'd say i'm between a min/maxer and just a dude who likes to play efficiently without crunching the numbers too hard.
This kinda thing applies to a lot of the game even, I mean look at the talent Zombie, you should NEVER take it cause it is horrible in every way possible and you could gimp your character completely if there isn't a talent switching mechanic in the game, it is just that bad a talent.
Last edited by Kokoro-Sensei; 22/02/17 11:04 PM.