The people who decided that they don't like tanks in scenarios is the entire player base. We tried getting GVers into scenarios many, many times with a lot of effort each time. The last time we tried it, three people went into tanks. Scenario players prefer the air-combat part of the battles.
Altitudes picked in scenarios are not a mystery.
Scenarios are crafted to make the experience of flying in them like what you read about if you read accounts of the action in the battle -- to be representative of that action. For scenarios where there was lots of high-alt action (8th AF vs. Luftwaffe, for example) there are fights that happen at 34k. For Eastern Front (and Tunisia, Rabaul, etc.) where there was almost no action way up that high, and almost all of it was lower, we craft it that way. If we didn't, fights would be at 30+k, which would be unrepresentative and highly unrealistic.