1: With the advent of both the procedural craters and the wing/fairing mods, I was wondering if you'd considered making procedural fuel tanks. That way we players won't have to fiddle around with stacking various different length fuel tanks. It would also reduce part count significantly. You'd also get rid of incredibly wobbly rockets. You could also make them tweakable, having a system where you right-click the part in the VAB/SPH and can select from a list of options. For example, a 1.25 meter tank could have options for type of fuel, then it would bring up the maximum capacity and you could determine how much of that you want to fill. 2: Single command execution. I had an idea recently to create a multi-planet orbiter that would release 2 satellites in different polar orbits at each stop, but I found executing it insanely complex due to the limitations of staging commands. I was thinking that you could have it so that parts with a probe module would be able to execute a single command upon decoupling as long as they had adequate resources. Something like a single maneuver node for each part. 3: EVA tethers. I know that sort of idea is blasphemy for a Kerbal, but the possibility of a tether (which you can then cut) would make it a lot harder to accidentally send your Kerbal on a reentry trajectory. 4: IVA joystick. It would be great to have an in-cockpit joystick that could either correspond to an external joystick or be manipulated through the mouse. 5: More scientific equipment functionality. Knowing heat is kind of pointless at the moment, considering I've had Jeb ride what's essentially a chair with a parachute through a Eve reentry. I'd love to be able to have instruments that give you terrain info, snap photos (making probes far more interesting), get resource information for bodies, and whatever else others can dream up. 6: The ability to secure items to surface. I don't want to worry about a Munbase flying away because of a collision. 7: When asteroids are added, make them movable. Obviously it will have to be a major feat to move them, but being able to move some orbital bodies around has a lot of potential. 8: Duct tape. 9: Paint. Who doesn't want to be able to change the colors of their ships and planes? 10: Testing facility. As amazingly fun as it is to test out a new spaceplane by seeing whether or not it would crash, I'd love to be able to put it through a wind tunnel. 11: Motorized part movement. It's somewhat possible with mods at the moment, but it's a bit difficult to create variable swept wing aircraft. 12: More symmetry modes and ability to switch between VAB/SPH symmetry Edit: 13: Part embedding and intersection. Mounting landing gear on a fuselage and having them fold up into the body through an 'embed' option. Adding a 'cut into' or 'intersect' mode is added along with symmetry so that you intersect, removing clipping problems without debug. You'd even get some great failures from people who accidentally intersected an engine poorly. 14: For career: promotions. Generating public interest in projects could add a nice dimension and impetus for people to try new and insane things. Obviously, being KSP, there has to be some sort of bonus directly related to how dangerous a mission is. 15: Flag/logo creator. It's pretty easy to do outside the game itself, but it would be nice to have it in-game, maybe even with the ability to see how it looks on a flag, spacesuit, rocket/plane, etc. 16: More in-game clocks. The ability to add a custom clocks/timers/stopwatches would be really useful. 17: Compiled stat tracking. Just having a place where you can see the stats from all of the flights you've run. 18: Gyro-isolated parts. Imagine being able to rotate your ship for starboard docking, but keep your command pod facing towards the craft you're docking with. 19: Sort of related to 18, axles, movement sockets, etc. 20: Not sure if it's been suggested elsewhere but: Extreme weather. I'd love there to be occasional hurricanes and massive thunderstorms. I'd love to see a planetary dust storm on Duna. Hell, throw in solar flares too. 21: Olympus Mons. Tallest mountain in our solar system should have some representation on Duna. More famous geography having mirrors in the game would create some great locations to visit. 22: Fires/heat failures. Have some overheated parts simply catch fire or simply fail/shutdown. You could throw in extinguishers or require fuel/oxy cutoffs to deal with fires. It would also be fun to see fires around crashes once vegetation is added to Kerbin properly. 23: Hamster ball for Kerbals. Kind of self-explanatory, just something I'd find amusing. 24: Landscaping. Not just basic stuff like beautifying your KSC with statues, shrubberies, etc but actual terrain shaping, possibly even on other bodies. No terraforming, just simple 'flatten out this bit of Mun to act as a landing pad' or 'make this part of Eve flatter to create a runway' or even 'turn this hilly area into a giant launch ramp for Jeb'. 25: Assisted launch. Like on an aircraft carrier. Maybe even make an electrically powered rail system for space stations to give small boosts to refueled ships/escape pods. 26: Probably been suggested to death, impact deformation. We want to make craters of our own, we want to see a plane actually stick into the dirt. Though I'm thoroughly amused by bouncing debris, I'd love to see it have an effect.