I love mechanized commander, Dodge just shuts down early Kubel play plain and simple. The refit ability is lesser known but its wonderful to get your resources back, sometimes I call in Assault Engineers, hop them out and refund the HT.
Assault Grens are very situation dependent and map oriented, use them in Urban combat only. I don't think they need a buff they are perfect for 0CP call ins, wonder how they scale vs Assault Engineers tho?
Grens spam is THE worst thing you can do with OST. I think building max 3 Grens is good enough with MG/Mortar support to hold the line. Don't forget you need muni for med bunker, LMGs and/or PGs. Also, I usually go scout car against USF and kite from far.
I just want the problem to be actually solved. Having only 1 OP heavy doesn't change the fact that the 1 heavy is still OP.
One heavy can be taken down by 3 Shermans as Relic rationale for not adding Pershing Tank. But, when you have 2 KTs or JagdTiger + KT late, that is when USF struggle.