I was planning a cold snap build which I later discovered was almost exactly like yours, except mine is a CI build. After watching your video (very helpful btw, thx), I started to worry that I was setting myself up for BIG TIME mana problems. First I need to point out that my character will not be a hardcore character, so my need for survivability is not quite as great, however I would like to still run end game maps without dieing a whole lot. I assumed that running a high level clarity gem boosted by aura passives, along with the mana leech from Bereks Grip, would provide me with enough mana. Your build though with its gigantic EB mana pool and regen, along with your comments, have me wondering whether my build will work as I had intended. Please let me know what you think, and whether there are any other options. I have linked the items I plan to use, along with my build, and how I would do a life/EB build similar to yours but for a witch.
By the way, I plan on using Freezing pulse as a secondary. I like having more than one dmg skill, and I think it would be really good if/when I get swarmed.
So as you can see I have invested most of what I have into the characters items. At this point all I need are a couple more q% gems and a helm. It would be super lame to have to sell most of this and buy life based gear.
Possible Life / EB build, pretty much your build but slightly modified for witch:
Please, let me know what you think.