Hmm... Well, I'm incline to think they should just remove Parry outright and treat it the same as Evasion... Replace it with Counter, and just give it some synergy with tanking... Something like;
"Grants a chance to preform an additional auto-attack every time your current target attacks, with an increased chance to Counter upon blocking, parrying, or dodging an attack".
That's still worthwhile when not tanking, it's just improved while tanking...
Really though... They could remove all stats and treat them like Evasion, and I'm not sure I'd notice... Itemization is just pathetic in this game... Secondary stats really need to have a more noticeable impact, IMO... People will always go for the best option here, because that's kinda the only option... If things worked differently, I could see people going for something like Critical Hit Rate + Skill Speed, because that combination is rewarding... Critical Hit Rate + Determination might still be superior, but if these stats had more of an impact, I can see the rational that would lead someone for favoring Skill Speed instead... It's a logical combination, more of your hits are critical, and you're getting more hits in... If the result of that combination was actually noticeable, I'm sure it would be satisfying to build your character in that way, even if it's not technically the best option... I mean, gearing Skill Speed can be noticeable, but for the wrong reasons... It's a really dumb stat in that regard, if you build it specifically you'll just run out of TP quicker and it's slowing you down instead... That's like making it so too much Accuracy has you missing more than you were with too little...
There is really just no satisfaction in stats, IMO... Parry is kind of the epitome of that... A Parry build is not satisfying, because it just doesn't do anything, even if you're main tanking... If it had a noticeable impact, then I could get the desire to gear for it... You wont always be the main tank, but you geared it for the satisfaction it brings when you are the main tank...