Okay, I'm back, and with a little more time to write.
So...for some reason, it occurred to me that D6 Fantasy might make a great system for running Spelljammer. I was in the shower at the time, which may help explain it but probably doesn't.
Ever notice how, sometimes, a game system will just leap out at you as a great option for a given setting, or type of game? I mean, out of all the choices you might have, one game above all the others will seem an ideal match to a given setting. For instance, you can hold up Forgotten Realms and say to yourself, "Well, I can run this with any D&D edition or variant, or Fudge, or HERO or GURPS or D6 or Rolemaster, really. But for some reason, I really want to use Rolemaster...!"
I do this a lot. I do not know why it happens.
It all points squarely at the subjectivity of enjoyment; that's the only reason I can give. Maybe it's just whim. But maybe, just maybe, it's alchemical -- a weird kind of intuitive, trans-conscious sense of what will add up to be greater than the sum of its parts.
And remember - this is all subjective. There is no formula; it just swings for you. I already had lots of fun playing Spelljammer using Fudge; it worked out very well. I just know that I have a feel for what a D6 Spelljammer game will be like for my players and myself, and it feels right.
By the way. If you read the title of this post and thought of Jem, give yourself 5 points. If you thought of Larry Fast, give yourself 20. If you thought of both, either get out of my head or pay rent.