Hi everyone, this is my first post on the forum. Not a great writer, here, but I was reading posts for some time now...
I am following the discussions about relativity, and I'd like to give my point of view on the thing, which essentially orbits around two points:
1) Technicalities
First, I may be wrong, but it doesn't seem to me that special relativity is that hard to implement.
For instance, it should be possible to calculate the slowing down of clocks by calculating their proper times (wikipedia) from the path followed by a vessel evaluated with respect to Kerbol, which boils down to a numeric integral easily performed by a computer.
It seems some people are focusing on slowing down the rest of the universe from the point of view of the ship (which I agree would be hard to do), while instead one could simulate the slowing down of the time of the ship with respect to the universe. This should be much easier to implement, since one could just use the Lorentz factor to slow down the mission clock, the consumpion rate of resources, and adjust (possibily, I am not sure) the thrust produced by engines. This could be done independently for each ship.
I don't know what's your opinion, but I would be already happy to see time slowing down, even without seeing Lorentz contraction or Doppler effects.
2) Education
Secondly, and most importatly in my opinion, I wouldn't underestimate the educational value that including SR would bring to the game. The huge success of Kerbal Space Program is deeply rooted in how it makes hard concepts more intuitive, so it seems to me very natural to move forward and include SR effects in the game. Wouldn't it be great if some kid discovers something about special relativity because he/she sees the clock of its creations slow down? Besides, it needs not be a huge effect: a few seconds / minutes over some years mission could be enough to trigger the interest and it does not require large fractions of c to be visibile, especially if one could compare in the GUI the ground clock at Kerbin to the mission clock on the ship. This should be included even if all other SR effects are neglected (which is the case anyway if large fractions of c are prevented somehow).