They should be worried, most people are unhappy with it as it stands.
The whole idea had pluses and minuses, when taken as a whole worked out to a plus for Americans. But by the time the far right fear mongers, the fat cat lobbyists, and Religious Fundamentalists finished their mangling, they've removed enough pluses, to make the package look like a bad idea.
We can only hope with this bill as a base, it can be tweaked in the future, to be a good thing for America. But with a congress bought and paid for by special interests, and a body of voters without interest, I doubt it.