The A34 Comet would do a number on both the MkIV's and the T-34/76's we have now.
I say HiTech should make like Christmas and give us the Panther and the T-34/85 at the same time.
You GV'ers wouldn't go to bed for 1 week.
Comet was a decent tank but only 1400 were delivered by wars end and non saw any real combat. The remainder of the British tanks were rather under gunned and were considered infantry support tanks. Again the Comet could compete but I don't think would make much diffrence or get used as much as say a new german or russian tank.
Look at the P-39. I saw the skies full of them the first week and now I see one about once a week and it generally doesn't stay in the air very long after it's spotted. I guess if HT was going to put 3-4 new tanks in the comet could be considered but as long as it's taken to get new planes in I would opt for something that people are going to use day in day out like they would the Panther of a T-35/85