They're gamechangers which you may or may not want. And also, I was mostly pointing to those talents as interesting concepts, if not necessarily balanced right. I like tradeoffs, but I agree they're hard to pull off, and not all talents should be tradeoffs. A lot of the tradeoff talents just don't offer very much for a big downside. Demon and Ice King are probably the worst offenders, but Walk it Off is definitely on the weak side too.
What if Walk It Off was how it is now, but it also gave you a 20-30% movement bonus while you were debuffed (and maybe buffed too?) To simulate you "walking stuff off." Maybe even a 1-2 AP (or speed) bonus while debufffed? Obviously not very helpful when stunned or hard CCed, but soft CC like curses could be beneficial in a certain way.
Here's another tradeoff idea for a talent incompatible with Far Out Man (so mages have a bit more choice, though they still need a few more talents):
Personal Mage: You have -5m range on your spells and scrolls, but they deal 25% more damage.
Numbers could use tweaking, but the general idea is to make a talent for spellswords or aggressive close-range mages in mind.
On Backstabber, I'm mixed with it being a talent. Admittedly, rogues don't have much leeway for talents, with Backstaber, Guerilla, Speedcreeper pretty much required, and Bully and maybe the Scoundrel talents as other obvious choices, but I do imagine backstabbing does take a certain amount of talent. I could see it going either way.
