Crit was never the important part about Wits in my opinion.
The most important part is initiative, wich at current state get crippled already at level 3 sadly and perception for hidden secret to dig and trap. Honestly I have no idea, why wits has a deminishing turn out but you get +1 initiative per level you gained.
Rage is a missbalanced spell that needs fixing and backstabbing was always there, regarding the fact that daggers aren't the strongest weapons, this part is probably still fine.
I just hope, they will fix the stat decay pretty soon, so we can start the real testing. The core system is so fat off, that discussing balancing details is hardly usefull. Becausing fixing the core system will change pretty everything anyway, I guess.