And I would agree with that for sure, The mortar, if it was needed for anything was build order luxury and diversification; replacing smoke with mortar, replacing fast flamer ass engy with mortar, replacing boring 4x rifle with mortar, etc. Not to neccessarily give usf something they never had or 'needed'(mg counter) because they obviously have vaulting, true sight, smoke, op light vehicles, etc.
Usf can counter mgs effectively without morter, although on some 1v1 maps it can be a real pain where you have to play significantly better ( micro wise ) than your opponent.
However, you will need smoke nades or flamers if Ost is camping buildings, meaning tech or doc choice to counter the 1st unit ost can build from t0 . Vehicles will counter mgs in the open, just like good flanking but can only be considered a soft counter to mgs in building, and in reality a light vehicle is better used elsewhere as an mg can simply stall in the house until support arrives taking relatively little damage or pop incendiary rounds once vet 1 and then counter its own counter.
Edit : The light vehicles I am referring to are M20 and Stuart. The M15A1 AA Half-track and M5 Halftrack are quite effective vs mgs.
The initial counter to mgs in buildings in coh1 was flamers. As the game progressed more options such as morter, sniper, m8 etc became availabe as usf teched. In coh2, if you want flamers you have to pick a doctrine which restricts usf options for the rest of the match and if your unlucky, as is often the case with assult engies your flamer will explode.
The issue is more about design failures.
Its not only the fuel to tech to nades but you don't typically have much muni either. A good player can make your early smoke/nade a very poor investment. Maps with critical buildings only complicate things because there's no guarantee for a nade to clear or even a damage unit.
Therefore, I think USF Nades are more for mid to late game, imo. This is due to the player having a small number of units on the field in the early game. A few units are much easier to micro and dodge. The mortar fills a gap for the USF core army.
As far as the tier goes, I think you are right. Also the pack howi, motor carriage and mortar feels redundant.
+1
Early nades will often bite you in the arse, especially if ost player not only survives with no unit wipes but teches quickly to t2.