A couple things I really want to see
1. I really want better space plane support. Papi lights at the runways, localizer and glide slope support, 10,000 times better aero physics, better re-entry targeting (so you can line up on speed / altitude / direction), things like that.
2. Passive science gathering (like in RP1) or automatic science gathering. Running 10 science experiments 30 times as I go from biome to biome and flying low to high in space is not what I consider fun. Let me build my crafts and fly them where I want to go, and don't make me miss out on science because I forgot to click one of the 15 science gadgets bolted on the side of my craft.