I have a radical idea. Have you considered 4-slotting Stamina?
Power Transfer End Mod and Chance to Heal self (gets you 6% Regen as a set bonus), with Performance Shifter Chance for +END, and a regular ol' End mod IO (boosted to 50+5 when available) essentially took care of my Stormie's END issues.
In Health (also 4 slots) she has a Panacea, Numina's Regen/Recovery, a Miracle +Rec, and a Miracle Heal (which grant a +2.5% set bonus to recovery).
Grab the Atlas Medallion, as roleki says, and you should be pretty good. Portal Jockey accolade helps, too. Together they add 10% to your END, 5% HP, and these boost every source of heal and endrec as well.
It's kind of odd that the Health procs benefit END and the Stamina procs tend to help HP, but that's the way it works. The synergy is excellent!
PS: Scientist is quite right about Hurricane, it's the main defense provided to Stormies. Don't put a KB->KD in that one, you want it to make the bad guys back off. An END reducer is a good idea, though. With practice, it makes an excellent herding tool.