It’s Heli EC. Large map size is exactly what I love about it, and it would be incredibly boring if the maps were smaller. Spending a few more minutes flying isn’t boring, it offers more complexity and uniqueness.
This is unnecessary; they should be accurate as possible. Evading SPAA fire is a skill; high tier Heli EC is less fun because there isn’t any challenge. It is correct that SPAA is very powerful in Heli EC, but this is something that is an inherent feature of the mode.
I agree that the spawn frequency of enemy vehicles needs fixing. When it works correctly, it is fine, but I think the long periods without any AI targets spawning is a bug. Secondly, convoys are a central part of Heli EC and spawning should favor them. You need to destroy them to have battles spawn.
This is something that needs to be done slightly for helicopters without any guided weaponry. For most other helicopters, earning SL with cautious play is absolutely possible. You also mentioned opening up possibility for J-out to spawn somewhere else. I disagree heavily with that, this is unrealistic and should be heavily disincentivised by the game.
I agree with this, it should be a few minutes longer, especially with cap points very far away from spawn.
This is one of the best aspects of the mode; the long match time is exactly what makes battles interesting. It allows for a solo player to complete a match given the circumstances. There is no harm in having a long match time; if you need to leave midway, you absolutely can.
Overall, I disagree with most of your points for various reasons. For many Heli EC players, what is needed is more unique objectives and gameplay. A smaller, shorter, and easier Helicopter EC would be bland.