Now, we have a complete comm system, a stable orbit space station , we can build our own space base on Mun and we have a lot really cool SSTO !
But space is really huge, i think if we can find some ancient artifact about Kerbals/Aliens , learn the history about them . Or finding other lifes include the cell form / Ancient DNA , digging some ancient fossil , it'll be really cool!
Also we already have a lot of easter eggs in game, some of them just like ancient building of kerbals . We can use them to build a "Story" !
What do you guys think?