As far as the future, with movies coming every year, I think we could see a Marvel like approach as well. Like it was said, it is already moving that way and I think it is probably a more profitable approach for Hasbro right now. As far as character depth, I could see a vintage like approach in a way there too (like, real vintage). Focus on the main characters and sprinkle in interesting looking aliens, etc. Honestly - and maybe it is the nostalgia of it - but the vintage line(s) seemed to cover what was necessarily pretty well overall. Sure, more is always better, but aside from a few characters (Tarkin, Stormtrooper Han, Jabba's Leia, RFT, etc.) they seemed to cover the most important stuff pretty well. I could see the same approach with new lines. Disney in particular seems most interested in OT era/feel stuff, and would maybe push for an approach like this.
I do wonder how much prequel stuff we'll see. As mentioned by Muftak, we may be seeing the end of that stuff eventually. It really seems like they are glossing over that era as much as possible right now, although some of it might be coincidental. I do think there is a pretty good chance that with all the characters we've seen done over the past few years, that our best chance for OT (or even PT) characters might be the 6" line (if that succeeds). It is definitely going to be interesting to see how things go once the new movie(s) start ramping up.