Nice to see a thread about War. I've been trying to come up with something to do with him for a while. As a small aside, his name is somewhat problematic when searching these forums as well as the wider web because his name is in the game's title. Oh well.
The suggested teams here are interesting. I've tried something similar to the BD build but with Keeper of Souls, valk and apothecary. It's alright but I haven't traited War yet so I'm not getting the benefits of having him in front just yet.
I heard tacet mention in one of his videos that War is often used as a caster where the goal is to buff his attack and then nuke the opposition with his skill. I wanted to explore this and came up with something that seems to be pretty powerful, however I haven't fully leveled all troops yet so I can't say for sure. Anyway, the team is as follows:
Valk does her thing, filling up Justice and the others. Justice hopefully loops with himself, healing Valk up front as well as boosting everyone's attack (good for skull spam as well as, of course, War's skill). Winter Wolf freezes the first enemy as well as places hunter's mark on them. Double skull damage from the Mark isn't bad at all, especially after a few attack-boosting Justice casts, which are themselves boosted by the frozen enemy. Additionally, Winter Wolf often creates a couple of extra blue gems which is useful. After a couple of turns War's attack is kinda high making his ability really powerful, often oneshotting whatever he targets.
At first I used Justice in the first slot, thinking his Armored trait would come in handy. However, his skill boosts all other allies and not himself, and so his attack remains low which I didn't like. I also don't really like using Valk up front but Justice helps keeping her alive and over the course of a game, generally creates more blue gems than Valk does anyway, so I'm not too worried about that.
I would replace Winter Wolf with a fully traited Queen Mab for more damage output and more frozen enemies but I don't have her yet. I've also considered Ice Golem instead of the wolf but he is completely mana blocked by War unless I place him above War but... I dunno.
Thoughts or suggestions are very welcome.