I'd like since Clark is Superman now...for the Legion to return and take him into their time. This was obviously not really feasible given the budget restrains "Smallville" was under at the time, but since this is a comic book...a three issue arc or something like that would be awesome..
That would be really cool. Since we're talking time travel maybe Clark could go back in time to the 70s and team up with the JSA in their prime. If anything it would be an excuse to see Carter Hall again. I really enjoyed Michael Shanks portrayal of the character and it was a cryin' shame when they killed him off.
Speaking of Hawkman... do you think we'll get to see Katar Hol in Smallville
? The Justice League wouldn't be the same without a hawk on the team.