The issue with Obama = Taft is the fact that George W. Bush was not and never will be a Democrat, or anywhere near Teddy Roosevelt for that matter.
If you want a good Obama comparison, look to Nixon and Clinton. Both of whom won their re-election challenges fairly easily.
Well, what I mean is, Obama is drawing severe fire from the left it seems much like how Taft inadvertently split the Republicans during his presidency. Now, I am quite possibly over-exaggerating it, but it seems likely that someone will rise from the Democrats or GOP and try to pull a Teddy Roosevelt in forming a brand new party, personally, I think it'll be between Ron Paul and Ralph Nader, though I'd wager Ron Paul's likelihood of getting on the ballots is far greater than Nader's.
As for Clinton and Nixon, well, I can certainly see, especially taking into consideration Jeb Bush saying that they shouldn't underestimate Obama's likelihood of getting re-elected.