Yosi-P did say that they tuned the Alexander Normal and Hard raids such that you need to farm Normal if you want to succeed in Hard. So there most likely will be a significant gap at least between AlexH loot and the entry Lv 60 loot. We also know that Lv 51 gear will not be higher than iLv 135.

My guess is:
Lv 55 at iLv 135
Lv 60 at iLv 140
Law gear and AlexN loot at iLv 150
Esoterics gear at iLv 160
AlexH loot at iLv 165-170

One thing I feel would be key is how Yoshi-P says the available iLv diversity will be wide. I'm guessing that it means different itemization at the top-end with minor differences in iLv (e.g. only 5 iLv difference) that may make a lower iLv item better for a particular job due to the itemization.

As tank though, we're probably still going to be looking at just Accuracy and iLv, unless they untie primary stats from the iLv.