"To be concerned about being grown up, to admire the grown up because it is grown up, to blush at the suspicion of being childish; these things are the marks of childhood and adolescence… When I became a man I put away childish things, including the fear of childishness and the desire to be very grown up." - C.S. Lewis
I would sort of like the PT timeline given a rest, but some actors could not reprise their roles later:
Ewan (as CW or Dark Times Obi-Wan)
Hayden (with the helmet off for CW)
Ashley (she might play a Dark Times Ahsoka in live action)
Temura (he can play anyone from a CW Clone to Dark Times Boba)
Ray Park (can be the half-Maul)
Ahmed (yes, JarJar could come back)
Natalie Portman (CW or Dark Times Padme - assuming her death was faked in ROTS as it should have been)
Ian McDiarmid (CW or Dark Times Emperor - this is already rumored - Palpatine better stay dead for E7-9)
Christopher Lee (CW Dooku)
Jimmy Smits (CW or Dark Times Bail Organa)
Joel Edgerton / Bonnie Piecies (Dark Times Owen / Beru)
A lot of talent from the SW cast could return.
If they did it now.
But YES, I agree and think SW got totally skewed to the PT / CW and that era has so much more material than the OT. But with "Rebels" I think the OT is coming back.
It makes sense they did it this way. The PT does not relate to much of anything they are doing now. Jaina Solo-Fel, Ben Skywalker, Allanah Solo have no relation to the PT in any direct fashion. Even if they don't go with these characters, while I hope to see EU continuity myself, Han and Leia's children (and Luke and Mara's) would have had no contact with most PT characters.