Zip, I feel almost in the same predicament -- I'm going for the first time this January with good friends who are excited about going but have not been converted to the true Disney obsession that I have since being introduced to these boards. So, I don't really think about this as my first time - I'll be saying things like 'hey, where's the orange smell on Soarin'?' and embarrassing my peeps to death.
Another problem is that at least one is not as hip into the planning aspect of the trip - he just wants to fly by the seat so to speak - and who am I to tell him otherwise?

So I'm happy to let him 'fly' but me - I'm going full tilt all the way, with my planned schedule. And I do plan, if no one else goes with me, to be that single rider in the Dumbo line. I

Dumbo, even though I've never been to WDW!
Yet another problem is just how fond I am of my con thread buds. And blestmom [Debbie #3], mrsdon [Debbie #4], and Soarin and now you will be at WDW the same time I will be. I probably won't get to bug Soarin and Mrsdon as much as I'd like, being that they will be working but blestmom and her kids better watch out! You'll be able to spot them pretty easily - they'll be the ones who are hiding behind anything they can find to avoid me and I'll be the one yelling, 'DDDDEEEEEEBBBBBBIIIIIIIIEEEEEEEE, where are you? Don't you want to go on Expedition Everest again? You're not avoiding me, are you?!?!?!?'
And, now, I'll know to look for the single rider 40something at the Haunted Mansion - ZZZZZZZZIIIIIIIIPPPPPPPPPPPPP, is that you?!?!?!?!?!?!?
My friends and I will have 'the talk' before our trip -- the talk that says that, since we all paid dearly to go on this trip, we can experience Disney however we wish. If those experiences don't collide, so be it - if they don't want to go commando with me, that's fine but don't tread on me, suckas!
So all that to say, I don't blame you for being disappointed - a best friend can be a poophead, too. Maybe y'all can have 'the talk' as a warning beforehand - so, if he does decide to go, he'll know that when you say Disney, you mean Disney. It could either scare him away or, like Breezy so sweetly pointed out, change his whole perspective.