Let me lay down some good points for you.
Since the merc pets tend to sit near you you'll be taking advantage of hurricane in a more comfortable way by keeping enemies off of them for the most part.
Plus the debuff from Hurricane can works wonders for your pets and yourself as a whole.
Freezing Rain meshes very well with the ability to help out Merc damage, since they mostly deal a lot of lethal damage.
Good/Bad Points To mercs:
Good: Mercs are usually easily controllable pets that will stick close at all times and deal effective AoE. Not only that, but your Spec Ops can provide very useful stuns and ToHit debuffs.
Bad points: Mostly all they deal is lethal damage, and another key points is that the medic has the shortest range of the group causing him to close in on far away enemies (plus his grenade attack usually gets him killed).
Good/Bad of Storm Summoning:
Good- Storm Summoning has amazing debuffs pretaining to defense, Resistance, ToHit, Endurance Recovery, and ToHit. Storm meshes well to keep you and your mercenaries alive against small to large groups of enemies based on the amount of patience and break frees you have.
Bad Points- Storm Summoning will have you clawing at your endurance bar if you do not run it correctly. That and the lack of any significant heal makes it a "dry run" build.
Overall I think you should take key guides on Storm Summoning and combine that information with Guides on Mercs, and that way you have a good foundtaion for both sides.
Basically you'll be a pioneer with this combo, mate.
Write a guide for us when you've made it all the way, hah!
Been looking for any guide material specific to this combo and haven't found any, nor any posts really pertaining to it either.
So, has anyone tried this combo out and how has it worked for you? Good/Bad points?