We know that Blizzard likes the active mitigation scheme for tanks - you hit buttons to generate resources to use to mitigate damage - and that I expect will remain unchanged.
You will hit Shield Slam and Revenge to generate rage to use Shield Block and Barrier. I'm not sure if anything new will be added to that. Is anything really needed?
I'd like it if our Tier 15 and Tier 16 2 piece tank set bonuses were just baked into our tanking style, but aside from that I don't expect the style to change. But with gear going to this level of homogenization, there's definitely going to be some seismic shifts in terms of how we go about doing it.
In a way, that may be all for the good - people trying tanking for the first time won't need an entirely new set of gear to do it.