The theory about why Wits/Initiative doesn't work in Tactician difficulty is that it's a bandage to make Tactician mode work. The real problem is that Tactician needs a major redesign. Just undoing the change to Initiative won't solve the real problem. For that, I think, it'll have to take a few months of time and feedback.
It's not Tactician-only, they screwed over all modes like this.
Why? Nobody knows. It's not like wit's additional crit is anything to write home about. If anything the reason why everyone stacked wits was because +5% damage isn't anything to write home about either. But they needed to keep stats "low" for PvP play. And thus, bandage upon bandage upon bandage; the MMO development cycle.
This bandage however was coated in poison.