I'm not sure we can say how independent voters will act as they are a notoriously fickle group. But I would not overlook the possibility Scott could have a negative impact in a federal race. Let's say the GOP candidate(s) said they agreed with Scott's decision to kill Obama's high speed rail plan. How would independent voters in Tampa and Orlando react to that information? Perhaps that alone might not be enough to swing the vote but eventually there very well could be a tipping point. Much will depend on the identity of the GOP candidate, how he or she runs the campaign and the degree to which the candidate chooses to distance himself or herself from Gov. Scott.
Conservative voters will obviously not vote for Obama. But if the governor's performance continues as it is, I wonder how motivated to vote they will be.
In any case, whether or not the attacks on Scott actually work, they will definitely continue. I already posted Obama's remarks on Scott's high speed rail decision. And just today Bill Clinton says:
http://www.tampabay.com/blogs/the-buzz-florida-politics/content/bill-clinton-calls-out-rick-scott-ex-felon-voting-rights