Republican could let reality to teach Obama a lesson. If the idea is worked out in reality, then it'd be good for America.
Though, As you know, fundamentally, Obamacare is betting on the idea of socialized risk. The more people participate in the curent system. it would distribute the risk throughout the system, then possibly it'd bring down the overall cost because more people contributing money to the current system. The pot could get little bigger, but is it safer or riskier?
Then what is the profile of the new participants? unfortunately these are high risk cases with disease, illiness, those who can't drive...

as a result, it'd make the current system more riskier. I don't know how many young people out there would be needed to support the additional risk and absorb the cost. they might even have health insurance from their parents' plan.
While Obamacare introduces no competition to the system to keep the cost down, HMOs would be the ones who take on more risk. I think they eventually would jack up the premium (initially, they might offer insurance at low price at the beginning like many car insurance companies do to lure you in, then they'd slowly raise the price).
I don't like the way Obama talks about his healthcare plan like he's bring a good thing to people. there's no good thing being created here, only tax and burden to Americans and businesses.