Based on history, and actually living through the entire lifespan of the REAL vintage lines, here's my thoughts on what to expect:
The Original Trilogy Collection will be devoted solely to figures from A New Hope, The Empire Strikes Back and Return of the Jedi. The preguel figures will probably take a 8-10 month hiatus.
In 1999, to coincide with the release of The Phantom Menace, Hasbro focused all of their attention on characters from that film. Similarly, the Attack of the Clones (Saga) collection was originally devoted to it’s own characters. However, after the first month and about thirty figures later, the Saga line saw the introduction of Original Trilogy figures.
With the forthconing release of the Original Trilogy on DVD, for some of us arguably an event as important as the release of E1 itself, Hasbro will likely concentrate solely on figures from the first three films leaving little time or energy for PT figures. If you think about it realistically, this is probably THE LAST hurrah for an exclusively OT based line.
Movie tie-ins are a way of life for Hasbro, and they've shown us time and time again, that they’re going to take advantage of the DVD release the same way they did with the theatrical releases of Empire, Jedi, Phantom and Clones.
Fear not, with the Original Trilogy Collection beginning in June/July 2004 and E3 figures undoubtedly debuting in April/May 2005, the OTC will likely only last ten months or so. Then, I speculate, all figures will funnel into the same packaging set aside for the E3 campaign. Perhaps a "Star Wars Universe" or "Legends" collection.? Time will tell.