1. Making the T key for SAS modules a toggle (on/off), so you do not have to keep holding it
2. Make the game continue playing when you shift focus away from game window. Have a pause/un-pause button.
3. Ability to SAVE your creation.
4. "Side Stack" option, for when you want to add new modules somewhere in the middle of your rocket. Right now you have to erase EVERYTHING below a certain point, just to add a module in the middle. Create an ability to set aside a stack, without deleting it, while you insert something, and then take that stack back and re-attach it.
5. Easier to mange, expanded view, stage configuration and set-up screen. As of now it can get extremely frustrating, and very confusing to managing and configure stage ignition and separation when you have a lot of modules.
6. Time acceleration. Waiting during the drift phase to see if you achieved orbit, or how high you get is painful.
7. Mini retro-rockets, for stage separation. Right now when you separate a module it drifts sloooowly away, and if you activate your next stages engines before you are clear you risk blowing yourself up. And while you wait, you loose precious momentum. Or, sometimes you separate, and the bottom stage still sticks to your stack. We need mini stage-sep retro-rockets, that you attach to a module, once this module separates the retrorockets engage, and quickly pull away the module from your rocket.
8. Escape stage rocket