Basically enchanters (even without FTx) have plenty of means to increase their mana flow and you wont ever really run out unless crazy stuff happens or you're the only enchanter at the raid. 4k is just a good goal post for mana. I sit at 4015 mana w/ GoB which I find pretty healthy and more than enough most of the time.
The ac results are nice but like Troxx said , 600 to 1300 is a pretty insane jump. For perspective, your average enchanter probably has ~500 ac (rough guess). Iirc I believe I have something like 800ac on my relatively decent geared enchanter.
My personal opinion is to take a balanced approach and require as little gear swaps as possible (ideally none tbh) but enchanters pretty much funnel into a particular set regardless of how you're building your enchanter. The only pieces of disparity I really see is shoulder slots (perception vs viik vs windwalker) , legs (silver chains vs iki vs SS silk) , neck (aary vs valtron)and belt (tunare vs Dain head) and everything else has a pretty clear BiS item. (Imho)
The HP / AC enchanter build is viable and great! I would love to have the dkp to try it out
[You must be logged in to view images. Log in or Register.]
But theres a very good case to be made for a balanced approach (which really isnt all that different tbh)
But just in case you ever feel like your gear sucks , I solo'd this chardok named while i was waiting for a rez in PoG the other day
[You must be logged in to view images. Log in or Register.]
http://imgur.com/ajR0yRN