I think the reason many people struggle with space missions is the dual application of key pressing with mouse pointing. People that play many other games in addition to star wars, specifically FPS's, will have no problem with the space mission mechanics because they are used to using keys to run around while aiming their mouse at targets. However, no previous mechanic in SWTOR required such implementation, as the only location specific mouse work people have to do is clicking on targets (if they are not keybound). Thus for people not used to aiming the mouse and controlling movement with keys, the heroic space missions would present a considerable degree of difficulty.
I use the mouse by itself and the only keys I press are for power conversion between blasters/shields or activate EMP/Anti-Lockon. It can be done this way and mastered as well, but it takes pratice and a certain level of alertness to the patterns of the rail. If they figured out a way to randomize the missions, then the challenge might be increased a bit. It is the same track every time and can be memorized.
I'm not a hardcore player...I'm casual btw.