I like the idea of having Parry be a forced stat on all tank gear, but not taking the budget, similar to how a lot of late 2.5 healer gear had "free" accuracy on it.

Parry is terrible. Not only is it pretty pointless to stack due to the fact that it's unreliable and only reduces 20% of physical damage, it also has really bad returns per point - you need so much parry to see any meaningful difference that it's inefficient to stack even if encounters benefitted from high parry chance. However... parrying isnt actually -bad- per se. Parrying more frequently makes tanks feel tankier.

If every piece of tank gear had a chunk of free parry on then parry would become a stat that slowly increases as you gain item level without impacting your ability to DPS by stacking DPS stats.