I have an odd feeling that Bethesda will be the new Interplay - Just look at their line up. Themselves, inXile w/ Hunted (Brian Fargo's company) and Obsidian w/ New Vegas (Remnants of Black Isle, IIRC). If they can keep inXile and Obsidian working for them, along with keeping Interplay in line, I don't see why they can't help bring back the RPG market.

To be honest, BioWare have no major competitors. Bethesda do more open-world RPGs, inXile do action RPGs (Bard's Tale & Hunted), and Obsidian do a bit of everything. I don't think Obsidian could be the ring leader, but I think they'd make a damn fine studio under Bethesda's wing (I'm not saying Bethesda should buy them, but keep them close by).