I hate all of our level 90 talents, not only do you have to channel evocation for 5 or so seconds, it's so inconvinient, and none of the other talents are viable, (unless you are standing still all the time than the other one is)... I had so much fun in cata being a mage now I regret leveling this toon first..
I"m not really keen on either of those 3.. They're boring/dull and we should've gotten something awesome instead of these talents tbfh At the start I was really annoyed by invocation because i tend to forget to reapply the buff, but i've gotten more used to it now. It's just that sometimes I can't seem to line up nice crits for a good combustion and still have the buff up.. really shitty
Well, I was really not looking forward to the lvl 90 talents. Now after having used Invocation for a while, I can say that its not that bad. The biggest issue is to remember to reapply it but there are addons for that. On the other hand, whenever I do remember to keep it up almost continuously, I get questions. Questions like "holy #%$& how are you doing that much dps". So its all good.
Invocation on Frost and Rune of Power on Arcane are just givens, since they work a lot better with those specs mechanics.
I think I'm growing a bit fond of Invocation, since I am balanced around having to use it, and in those last 6 seconds of the buff I have to make an intelligent decision regarding CDs coming up and procs on my screen. Maybe it will also cause my warlock friend and guildie to give me less "lolmage" grief. :P
During beta and now on the live WoW forums there's been a slew of threads about the unpopularity of these level 90 talents. To be brief, the consensus is that Invocation and Rune of Power could both use some quality of life changes, such as the SP buff stacking in increments of 5, and removing RoP's cast time. I personally still enjoy Mages as a whole, but the 90 talents are my biggest area of concern and have been since beta.
I tested all 3 and concluded that I like Incanters Ward the most for most situations.
Main reason: It doesnt remove/replace the normal Evocation.
Secondary reason: It adds an additional spell that increase your DPS by a littel(6%) and if used right, much(30% between its short cooldowns) all this while still leaving good old Evocation that can be used normaly with the healing glyph.