AEC functions as a generalist that leans towards AT, and Stuart is the opposite in my opinion.
If the P2 arrived a few minutes later at similar timing and had the same lethality as a T70, it wouldn't be ok.
The main issue with the T70 in my eyes is its ability to easily wipe squads on retreat/its accuracy on the move.
T70 is probably the WORST unit in the game in killing retreat squads, the scatter is massive, you probably keep retreating squads when they are on the last man and never have anything to cover them.
I lost count of how many times I chased squads across entire maps and didn't manage to kill a single model. Just change you play style.