As far as aeroplanes go, I would like to see the following:
Weighted tires. They wouldn't be any other way so why even bother with unweighted.
Standing and seated pilot figures at the very least.
Canopy masks.
Wheels separate parts from tires. (Or mask if molded as one piece).
All radial engines like Accurate Miniatures. (Pushrods and wiring harness as separate part)
Instrument panel like Monogram Kingfisher "High tech" kit. (Best OOB panel EVER) Photoetch panel with decal glued in behind it. Simple and effective.
Small photoetch fret with aforementioned panel front, seat belts, and gun sights (if applicable).
All instruction sheets like Monogram "Pro Modeller" series. Well written with reference photos.
As far as armor/vehicles go:
More realistic instrument clusters.
Would it kill them to include some data plates?