USF's Mechanized commander could maybe stand to be toned down a little. Beyond that, I'm not sure what else needs adjusting. USF's internal balance is so good right now that any tweaks to nondoctrinal units risk killing the tweaked unit.
- WC51 no longer can be decrewed.
- Mark Target and 155mm Artillery removed from WC51.
Standard Sherman dozer blade upgrade removed.
The WC51's proved itself as an excellent unit. The rationale behind giving incongruous command abilities in the first place was to make it worth building: it's easily worth building without them.
Removing the vehicle crew would force USF to repair it with their REs when it gets damaged, lowering its early game shock value.
As for the Dozer Blades, they're visually confusing (they make Shermans look like the 105mm Sherman Bulldozer) and are a buff the 75mm doesn't really need. The excellent new 76mm Sherman is enough in my opinion.