The whole thing is politics for 'we don't have a manned spaceflight program anymore'; if there's a bright center to exciting times, this is the point furthest from it.
I'm forced to agree. There's too many holes in this plan, and whenever the nearest milestone for space exploration is set more than 8 years away, it is more than likely that it will be delayed when the next President shows up. I'm relieved to see Orion return, albeit as an escape pod. Some of the work that's gone on can be salvaged, and there's always the possibility that it can be upgraded for operations beyond earth orbit.
I'm concerned about the switch to "Newspace" for access to LEO, but not because I think they're incapable. Groups like SpaceX and Orbital can succeed given the financial backing that Obama's plan offers. What I'm concerned about is how long it will take to come to fruition, especially since we're retiring the shuttle very soon.
Take a look at Scaled Composites; when SpaceShipOne flew in 2004, it was said that SpaceShipTwo would be up flying tourists by 2007. Well, it's been six years and they finished the prototype a few months ago. With all the work remaining, they're still at least year away. And keep in mind, this is just for suborbital flight; orbital flight is much more difficult.
I also have a hard time believing that the commercial model will be able to close, given that the ISS is the only possible buyer for at least the next decade. The only other possibility for another space station is Bigelow - I'll assume the Chinese can resupply themselves - but that company's schedule may be just as dicey as SpaceX and Orbital. Perhaps with enough subsidization it could work, but that might make it so expensive that it isn't worthwhile.
But my biggest concern is the plan to start design of a new heavy lift vehicle by 2015. There is absolutely no reason why the design work can't begin now. There's no real "game-breaking" technologies which are going to dramatically boost launch vehicle performance that are going to come to fruition in the next five years. As one of my colleagues glumly put it, "The only new rocket that's going to come out of this R&D is a bipropellant engine fueled with Hope and Change."
Don't get me wrong; breakthroughs in fields such as electric propulsion could make a Mars trip very feasible, and achieving them in 5-10 years are very realistic, but if you don't have the vehicle to put it up there, it doesn't mean squat. That's why I have a hard time believing that Obama's plan is anything more than a big smokescreen.