i have a list of planes i would love to see
The He-162 would be a fun bomber killer
The Do-335 would give a p-51 a run.
Spitfire Mk XVIe bubble canopy enough said
ME 262 with 50mm
In the MA, with 2X fuel burn the perked He-162 is going to have 15 minutes worth of fuel. This would relegate it short range interception (much like the 163), and 2x20mms aren't all that devastating. Further, I don't know how much I like the thought of going in on a box of B-17s in a plywood aircraft. It won't take too many .50 cal hits to make your 162 (and your perkies) disappear in a cloud of splinters.
The Do-335 was always a favorite of mine. I know it doesn't meet the HTC criteria of "having been deployed in squadron strength and seen combat", but it was ordered into production in 1944 and had the German aircraft industry not been under constant bombing it would have been. This would be a much better high altitude bomber interceptor for you - 1 x 30mm Mk.103 (65 rounds) and 2 x 20mm (200 rounds) package gives you more firepower, and you have a much longer range.
As for the Spit XVI, no thanks. If there was to be a Spit update, I'd rather see the bubble canopy, clipped wing variant of the Spit XIV.
Me-262 with 50mm? Why take the variant that they rejected? Instead I would suggest the Me-262 with the 24xR4M rockets package. This might be a problem though - the rocket package is pretty devastating to a formation of buffs and might actually unbalance the game.