I still think fire is excellent at removing units from buildings, and the Germans have two very excellent options of utilizing it, with one available from the get-go. And hey, pioneers aren't two man squads in this game and apparently without blowing up and/or dropping the flamethrower all the time I think it'll (still) be an excellent way to handle buildings early game for the Germans.
Rifle nades works rather well in most cases, (as in, when they're used appropriately, i.e. on infantry anytime they aren't in a building) and I think the main complaint against using them in regards to buildings is that they cost valuable munitions. Munitions that would be more appropriately used for flamers.
Every time a german player uses a rifle nade on a building they might as well be using a panzerfaust on an infantry squad because it's simply using a strong ability in the absolute wrong circumstances. IMO Rifle nades should pretty much always kill 1-3 full-health garrisoned soldiers--depending on the house of course--rather than barely scratching every unit inside equally. But I don't think they should ever be more effective or a replacement for a flamer squad. That and I think small arms fire should be more effective against garrisoned units, but that's neither here nor there right now.
And let's not forget that germans are provided access to mortars from their t1, despite that it's become commonplace for people to just pretend they don't count because they use indirect fire and are support units. A mortar punishes and eliminates the advantages of stationary enemy positions rather than dealing direct damage to a specific unit. They also can provoke an enemy assault upon the mortar that not only by definition breaks the static gameplay of camping, and it can easily be kited and/or intercepted by anticipatory german forces.
This is exactly it. Germans have plenty of ways to clear buildings. It's just that most of the time they rather invest in things like LMGs. Soviets on the other hand can only invest in upgrades or molotovs which are good vs buildings. If there was a soviet upgrade like the lmg then they would most likely have a similar problem.