If you think M8 insta wipe ability in early game is fine, than according to your logic Schreck blobs and KT squad wipe is perfectly balanced too....
It's not insta wipe.
Insta wipe are B4, Stuka, Sturmtiger.
Units that are wiping all the time are KT, TA, ISU, KV2, Bulldozer.
But those units can wipe with every shot.
M8 need to pay 50ammo and still you don't have 100% chance to wipe (you are acting like every shot = wipe).
What's more, did you hear about Puma? Becasue Puma can counter M8.
Oh.. but I forget... Calling Puma will ruin OKW meta Volks->Obers->Panther

Or even raketen... 2 raketens in building can do the job really well.
And Ost should get 222 to counter it (with upgrade) but first Relic must rework this unit because it's useless.