Disneyland's Space Mountain I would be much less precious about. Not just because I consider WDW my "home" resort of the two, and therefore inherently care a little more, but primarily because:
1. I don't think the layout is that special at Disneyland.
2. The exterior isn't as impressive as MK's.
3. There's nothing TRON or Cosmic Rewind-like at Disneyland, so the resort could use something like that.
So if Disneyland got a complete re-do as part of the revamped Tomorrowland, that would probably be pretty cool.
But I think there need to be some creative and historical guardrails guiding whatever happens at Magic Kingdom.