Ok, stupid question, but humour me here...
Why wouldn't you put Palpatine on a Sigma Squadron Pilot? While I realize that's an extra 4 points, Darth Sidious' main job is to affect the entire board for as long as possible. Couldn't you just cloak the sigma and fly it around like a pesky pest around the edge of the board?
You lose the 3 die attack from the shuttle, but you're rarely shooting at closer than range 3 anyways with the OGP. And the Phantom should be much more difficult to focus down.
Also, if it does make it into end game, you'd most likely have more success with the Sigma than the OGP to finish off your opponent (and you'd be holding onto a few more points if your game goes to time).
For all I know, this has been discussed and put to bed long ago, but if anyone has any input on this, it'd be much appreciated.