We know that all the Ep7-related books hit shelves in September. That would certainly be a good time to release the OOT on blu-ray.

May the 4th would actually be the perfect time to make such an announcement. Better yet, they could say something about it at the convention in April and then debut the OOT trailer on "Star Wars day." May 25th would be even more appropriate, but I'm guessing Disney wouldn't want to distract from Tomorrowland's theatrical release.

ETA:

CatBus, I was simply referring to Disney hyping Ep7 (we've now seen an actual trailer more than a year in advance of its release date) while staying completely quiet on the OOT (it's been more than two years since they bought Lucasfilm). They've actually stayed quiet on the OT altogether. I suspect you may be right about them continuing to sell the SE as the originals.

Something I could definitely see happening is a 3D theatrical re-release of the OT-SE in September, minted from that new 4k master RMW cooked up. They could follow this up with individual blu-rays (which would include the restored original versions) in early December.