Hey buddy, thanks for trying! I tried to differentiate ASE a little bit from AC with the throttle - you're supposed to stay in the ACM window for dogfighting and general combat which is why the throttle is manually set, but you can play it perfectly fine AC style by double tap-and-holding the throttle keys.
Regarding the missile switching, unfortunately the D-pad is reserved for an upcoming mechanic, but I'm thinking of actually limiting weapon selection to 3 selectable options for a future balance pass. I think this would hopefully strike a balance between the multi-weapon loadout people want, and encouraging players to try out different planes. Hopefully this will also make swapping weapons a little less tedious too, but I guess we'll see how it's received.