Block value isn't a perk, it is an insanely nice tanking stat. Yes all warriors will use T5 over timewardens/karazhan legs... FFS thats not even a valid question.
Calling Timewardens the best tanking legs in the game just because of the stamina... thats just classic. With that logic you might as well go collect some green items of stamina and call your tanking set the best.
I think the problem here is that you clearly under value armor when higher armor values decrease your damage taken by SO much these days. Anyway as noted above its a silly argument since they are getting buffed again in the next couple of days, just rethink your "best" tank item theory mkay
Oh, and you can never have too much defense... its not like it gets any worse each additional point you get :P