Lee/Grant tanks for the allies, M7 Priest for the americans (imo, maybe an unlock with the 105. Priest would have vcoh range without the supercharged arty rounds, so youd trade mobility for range), maybe the Chaffe/Stuart Rhino as well. We could even add the M4A3E8 Easy Eight; sherman with a tad more HP and an M10 gun.
easy eight might be cool. i'd actually make it a 76mm sherman with an increase in speed and acceleration equal to the buffs given in the bottom armor t4. May 100+ hp like the Jumbo but it would still retain normal sherman weaknesses but be more agile