Agree, it's too late to be effective. What's the point of a Greyhound at the same time as a Stuart or Flak HT?
You could say it's an AI specialist and could pair well with a Stuart, but the canister ability is severely underpowered, so along with needing an MG upgrade it's a munitions sink just to get any AI power out of it (probably it's like this because CoH1's Stuart cannister shot was so massively OP).
What about making it toggle ammo like the sherman. AI could be the explosive shot like the aaht with no suppression for consistent damage. AT could do stuart level damage with no AOE to bull light vehicles but get beat back by the PUMA