you can't use nades early on as okw because you need a fast schrek and they don't perform the well
isg is expensive as **** and rather useless in my experience
aa ht: inf in buildings should not force you to one strategy
sturmpios work well against houses IF green cover is near by otherwise you just bleed a lot of MP
infiltration grenades are the only tool to really clear houses but only doctrinal - and they are overkill
penal flame-thrower for volks!!!!! (imagine the blob from hell burning everything and blowing tanks up left an right)
i read somewhere that stun-nades are good vs houses maybe if sturms get those at vet 1 ?
OK, don't go grenades early then, get the Kubel and make him crawl into every house. Also Shrek does pretty good damage against houses. You can also get a Raken.
ISG is very expensive, but think about getting it on urban maps, it can easily pay for itself.
Sturms are great against units in garrison, and then you remember you are using a faction which can build green cover.
As OKW you are supposed to have a weaker early game since your late game units are so strong.
Also houses don't force you into one start it forces you to consider going for AA ht. You don't have to get it, you can avoid areas with houses on many maps. You can also get a puma and use it. Remember to damage the edges of a house to make it collapse.
OKW are relatively weak to houses, but they get tons of tools to deal with them as the game progresses.
This discussion has also moved to the problems of garrison units for OKW and not Sturms, which are amazing in the right hands.