Des Kovak
Knucklehead
I would enjoy a film with McGregor as Obi-Wan between the two trilogies, I think, but making it a whole other trilogy again is perhaps taking it a bit too far? It would probably feel very stretched thin, like when they made The Hobbit into a trilogy as well. That should've been one movie too. That said, the EU has some great Obi-Wan content from that period out there, like having him face down A'Sharad Hett when he started slipping into the Dark side. They're obviously not going to use it, but it goes to show you can put together some good story content for it.