There are a couple of features that I am looking forward to a little extra in this patch, for example I intend to start burning through instances like there was no tomorrow (aliens attacking?) with my dk, maybe even my warrior, due to the new Call to Arms. I like tanking - I just need a little more incentive to stand the douchy pugs. Maybe this will be enough, we'll see
I previously pointed out that players already have a tremendous incentive to enter dungeons as a tank, so if they are going in as dps nonetheless then no reasonable cash bonus is going to change it. However, I overlooked that there's another source of tanks than people who would otherwise have queued as dps. Alts!
Warcraft is an alt-friendly game, and many people create alts once they have their main character maxed out, for some definition of "max". When people decide what to do with their time, they choose between things like daily quests, taking an alt into a dungeon, playing the auction house, working on achievements, and so on. Call to Arms will tip the scales of that decision toward running dungeons as a tank, and the scales there are already pretty balanced.
I predict we will see a lot more tanks in the dungeon finder. We'll also see a lot fewer people doing dailies, participating in battlegrounds, and all the other things people would otherwise spend their time on. That's really all fine with me. I find dungeons the best part of WoW. It's not a very good PVP game, but it's a wicked cool multi-player PVE game, and nowhere do you see more multi-player PVE goodness than in dungeons and raids.