Comets and Panther are very similar. Comets have unnecessarily effective gun versus infantry. Comet need the same gun as Panther. Chosing commader/MG upgrade and if you pick commader upg., replace smoke with HEAT rounds (with MG upgrade, keep smoke).
I am fine with a Comet gun nerf vs infantry, as long as the auto grenade launcher isn't disabled from Vet 3. That thing is awesome. On the flip side, I wouldn't mind that being moved to Churchill since it makes more balanced sense, and would give more motivation to get Church tree. I still go Church in 4v4s if my teammate guarantees comets, as I like flamethrower/MG terminator engies too much.