A terraforming starship module sounds awsome. It can upgrade any planet by 1, but it costs more for the initial terraforming event, drops, and then increases exponentially as the planet quality increases.
(#877) The tabbed build menu would be great (with lower techs),. Using tidal disruptors late in the game has you waiting a few hundred turns for an industrial sector to be built, it'd be nice if you could choose a more basic factory first.
OR - rename the land structures so they look similar. I.e. Farm - Basic, Farm - Xeno, Farm - Advanced etc... I hate when the name changes and I can't easily find the trype I'm looking for.
spending sliders - One for research (0-100%), one for production (0-100%), and a slider that switches between military and social %. I hate how the current sytem doesn't let you say full research and full production without messing with the individual bars.
population full - Please warn the player when a planets population is maxed out!
Thanks, I'm sure all of these have already been mentioned, but I wanted my voice heard too