My thought, and it comes from a broader wish for MMO's in general, would be to involve actual puzzles rather than just jump/push button. Providing a way to solve some in-world puzzle would allow a little mental challenge and pretty much open the experience up to anyone. We already have semi-twitch related play with our combat... environment exploration is interesting to a point but not that meaningful without some actual mental variations (story/puzzles/world events). Otherwise I'm having a blast. This is a polished MMO release and is fun.

^ THIS ^ Essentially I've been playing a Sith [inquisitor] Sorcerer and a Jedi [Consular] Shadow tons. Both are amazingly versatile (tho all the classes in this game are pretty versatile). Because of this it can be hard to understand which powers to use. Just be patient and read a little and you'll find this class is insanely powerful. I've found my Consular Shadow easier to play than my Inquisitor Sorcerer but they're both pretty epic.

From here on I will refer to this power as Force Sandblast! That is just so win. Perhaps I'm easy but I love both the Consular and the Inquisitor powersets. Sometimes for humor and often for coolness.

Having also come from CoH/CoV I am used to the idea of having multiple builds. They made sense within that game's framework, though. In WoW I dual-spec'd a Paladin but it was for very off-moment times. In the end, to me, I am in favor of choice--and like the OP said especially later as this game matures and we all (including Bioware) have more experience with SWTOR gameplay. While I understand the fellow who suggested a driving metaphor for playing different classes I also do "get accustomed" to playing any individual character a certain way. I'm not averse to suggesting to a team that I could fill in a needed gap but I am averse to teams demanding players change rolls (in general). When the team is used to playing together, however, it's just a matter of communication and team planning. So, after a year this thread should have even deeper insights. In the end if Bioware implements dual-spec they will probably have lots of game mechanics in mind. I'm all for player choice. Whether I chose to dual-spec will depend on whether it's useful for me, however.