With Mists now in beta, it's easier than ever to check on the differences between classes in Cata and Mists and it's really quite apparent that Mists is where the modern versions of classes got started - especially tanks, as that's the expansion where active mitigation started.
What are your thoughts on the decision to change WoW in such a drastic fashion? Even up into Cata, a majority of your mitigation was passive (through mastery, dodge rating, and so on) with each class having a few short cooldowns (typically anywhere from 30 sec to 5 mins in length) to amp mitigation as needed. Class resources like mana, rage, etc were spent primarily on damage or other things. Mists changes this to where resources will primarily be invested into mitigation skills, with passive mitigation being quite a lot weaker - warriors, for example, will gain the two charges of Shield Block that they still have today in retail and will gain Shield Barrier (which is largely just Ignore Pain), while Shield Slam transitions to something similar to retail where it's free and *generates* rage rather than costing rage.
I guess if I had to draw a halfway point where the separation between "classic style" and "retail style" class design lands, it would be between Cata and Mists. I'm still very much excited for Mists Classic, but I'd forgotten just how massively classes changed between Cata and Mists (and of course the new talent system is also quite a change!)
Oddly, I'm wondering if I'll end up being able to enjoy retail gameplay more if I've spent a year raiding and playing on "retail lite" Mists Classic :P