I rarely play US, but the Stuart seems lack luster in terms of damage output. When I play against it it seems annoying at best. I'm able to field a Pak or a pair of scout cars before it hits... I don't see the issue
There currently is a bug where any Allied vehicle that is decrewed and recrewed again while the Pershing commanders 'combined arms' ability is activated starts shooting like a bofors. All of them. And this is most noticeable with the stuart since the stuart comes early and with the bug decides the game. That's what he's referencing.
Yes I know it's a bug, I'm just informing you here.