As a faction, your options are Geomancer, Swarm, Battleleader and Sever. Too bad that the devs havent got a clue how to balance a champion that is not straight forward, so Sever (AoDiv) is pretty much not a choice.
Ranged build-up champs are also pretty good vs summoned. I used to run a SL/Paladin deck built around building angels up to high dmg. I haven't ran it since the revamp because I cannot use VW's DMZ to protect against spot remove, but if you can build a ranged champ build-up deck, those work great as well. Most summons are physical dmg so I guess physical dmg hate is also an option and maybe even melee dmg hate as most summons are range 1. If you are feeling pain from Trees you can run DMC, it's a wonky champ now but it'd be good against mid-font roots.
I run quite a bit of ranged in my BG, 2 hoolies, 2 windfuries, 2 magister and a DMC, and my melee has ranged poke like master axemen, and talgar, but I totally got stomped by a SP/FS beast BG with spirit of the mountain. Just couldn't handle that lol.
windfuries are a no go, run scarlets instead, they are plain better, and they bring both fire and magic damage, so less problems with trees and ghosts.
Against low HP summons like skeletons or spiderlings, clockwork swarms can go hogwild. Call to War style spells or more tanky summons though and I dunno.
Once battle leader is priced correctly the human side of IS will have 2-3( working on 4) battle leader champion options to help punish swarms/cheap champ spam.
Yeah after seeing your bg a few times I think yours has the same problem as mine being that there is not much/any magic damage available to you. So my guess is that spirit was trolling you a lot and you got stuck fighting less important champs/summons (or at least I can imagine that happening to me after facing meh trees). I think that scarlet is an annoying, but necessary rune in order to counter ghosts/physical resist champs and keep in the theme of drunken dwarves :/ Possibly run an Ethereal Hammer which would go with your ranged hammer barrage thing, would go well with master axeman (He will have a hammer and an ax) and it could theoretically be returned to your rune dock and refund its cost. But really there must be a reason why I don't see people using this rune and scarlet might be easier...
I think i'll squeeze in a second scarlet and edit his upgrades a bit to drop his cost by a few, I like having good burn but firestrike is pretty lame and I only use it when they get close, so no point in boosting that beyond rank one. Thanks for all the input guys.