I feel like the Star Wars action figure line should be 3 3/4" scale, since that is sort of what started it all - and at this point, many people have so much invested in that scale with figures, vehicles, beasts, playsets, and displays in general. That being said, I've been thinking for awhile that a 6" collector line would probably come along at some point, and I'd be ok with that too.
Like everyone else, I'm low on display/storage space too so that would be a big consideration for me if this line came about. However, I've been buying Marvel and DC stuff in that scale for years now, and do enjoy it (aside from the space they take up). If they did a "Legends" style line, I think it should be kept very limited (20 or less per year), and if they came out of the gate with some OT characters (and they were well done, of course), I'll admit I'd likely bite on at least some of them.
Prior to the Disney/Episode VII announcement, I was sort of thinking that a Legends line might be the shot in the arm that the brand needed. Now, it might be neat, but I would hope things would be back to 3 3/4" by the time the new movies hit (or, more likely, they'd have both scales running at once). The one thing I would worry about some is that it seems like Hasbro is slowly shifting to the Mattel model with boys action figure lines, where they put out a cheap, small scale line "for kids" that is mostly crap and then have a more limited (and often harder to find) Legends scale line for "collectors". I know when we get to the point of the new trilogy (and its toys) hitting, I'd be most interested in the 3 3/4" figures, vehicles etc., and I hope they don't start cheaping out on that line. Figures like the BP Bespin Luke are one thing (despite the lack of articulation), but if things start looking like the Ultimate Spider-Man, Dark Knight Rises, Green Lantern, or upcoming Iron Man 3 stuff (that we've seen) in that scale, yikes.