Ive played their (the devs) dark messiah game on the 360 and the player had to use magic potions for the non regen mana and i can tell you now that they didnt balance that cause they gave you so many that it might as well been regen. So im just basing my opinion on their past work, if they manage to balance this then fine yeah no regen will be fine but if they dont i see it as a waste.
That is a game with bad design regarding a rescourse system so there is no point discusing that.
The game isn't designed around mainly using powers. It's designed around balancing Stealth and choice through level design. So you will be picking your playstyle MAINLY and then which tool you would like to use. A single power itself has proven to be a really powerful tool, so I believe that the rescource for stopping time and other massive spells that can be used offensively are balanced.
I never said it was for casuals. You and Fearabbit seem to misunderstand what makes a good game. It's not challenge it's depth. If you have an endless rescourse for using you abilities, even a high one, all depth will be lost. There is no choice or second guesing in that. It's just do and gain great results. No skill, no deep thought required, just a simple press of a button and your brain reacts so you feel powerful.
If you want to focus on spell then spec into them. Maybe there is a way to spam abilities if you go for a full spell assassin. Maybe you can go a hybrid and gain every bit of satisfaction you require out of this game.