Disney will probably never build roller coasters as wild as Universals, it's not that type of park. R'n'R is probably as 'wild' as they'll get so if you're waiting for Disney to suddenly change tact, you'll probably be in for a long wait. When you ask "Does anyone think tron "the ride" is the best use of this precious space", you'll get different answers from different people as it's all subjective.
Firstly for a family that loves white knuckle rides, the Magic Kingdom really isn't the place for them to go is it? Islands of Adventure is where they should head as that's the demographic that park is more suitable for. For a family who likes Disney and it's magical, nostalgic appeal, the Magic Kingdom is far more suitable. It contains some 'exciting rides' that go faster whilst not built to challenge the courage of the rider and get the adrenaline really pumping, rather it tells stories in a more gentle way.
Bearing that in mind then I'd imagine that a great many people will really enjoy this ride and it will perhaps allow younger kids who are intimidated by larger, faster coasters to ride with their parents on a coaster of sorts. Whilst it doesn't sound like this is the attraction for you, it's designed to be in a park where a great many people will ride and enjoy it. I can't wait to ride Universal's VelociCoaster this October, probably more so than Tron (whenever that opens). However a coaster like that was never going to be built in the Magic Kingdom, it just doesn't fit.
As for "Does anyone think tron is anything special or remotely clever as a roller coaster?", well again it's subjective. If by 'clever' you mean themed or a good idea, then I'm sure many will say yes. The 'theming' is based on the movie and some of it looks pretty cool and captures some of the bike chase scenes rather well. Is it 'clever', again subjective but I'd say yes to that too. They've taken a coaster of sorts and incorporated it into a scene from the movie using a good number of sets.
I'm not criticising the VelociCoaster when I say this but if we're talking theming and cleverness of rides as coasters, the VelociCoaster is probably less themed and less clever than Tron. The videos I've seen show very little theming other than some static dinosaurs and sound effects of them chasing you? I'm saying this from the perspective of somebody who personally believes the VelociCoaster to be the better attraction, I'm certainly not trying to put it down. I'll ride the VelociCoaster for the speed, the drops and loops and I can't wait to go on it. It's not a ride that needs special effects to add to it, it's fine as it is and you're riding it primarily for the thrills with the connection to the film being extremely minimal to none existent with regards to the enjoyment aspect.
I can pretty much guarantee you that the designers of both these attractions will have given no thought whatsoever to the other attraction and made comparisons, they're not competing for the same demographic at all. We can debate which is the better attraction for individuals based on what they like from a ride, but that's so subjective it's almost futile. If a large number of people ride Tron and enjoy doing so, Disney will have achieved their goal as that's their objective. To make a roller coaster as 'good' as Universals was never their goal if 'good' is defined as faster or as frightening in my humble opinion anyway.
