I'm still placing my bet on #1.
It's mostly software that needs to be upgraded. How hard can that be when the EX1R already exists?

Everybody has their own favourite out of all the improvements that the revision has brought, but two of the favourites are cache record and native SD capability. AFAIK they both need enhanced hardware. Maybe others like "dub all clips" could indeed be added via firmware.

But anyway, Alister's told us that no plans exist for an upgrade. It then becomes a question of what you count as an "upgrade", and what as a new model, discontinuing the old one. We'll see.