Clinton himself claimed he could have won in 1988, but that he was not prepared for the Presidency at that point.
If Clinton's nominating speech fiasco repeats itself throughout his 1988 campaign, I can't see him winning.
Clinton is going to face a much tougher campaign than he did in 1992. He has to run against the Bush 1988 campaign. How the race turns out depends in large part whether Atwater can sink Clinton like he did Dukakis. I'm not sure whether Clinton's infidelities would have the same effect on the electorate as Willie Horton, and whitewater as a scandal was still years away as far as I know.
Clinton probably does better in the south than Dukakis did. At the very least, he wins his home state in Arkansas.
If his infidelity doesn't sink him, and Whitewater doesn't show up in 1988, then I think Clinton has a good chance of hanging on to more of the early lead Dukakis had than actually happened in 1988.
It really depends on a lot of factors though. Obviously Perot isn't running, so if you happen to believe Perot's the reason Clinton won in 1992, then that's going to hurt him. Also, the recession which also arguably propelled Clinton into office in 1992 hasn't really happened yet AFAIK, so there's that.
Due to those factor, while I'd like Clinton to win in 1988 (and 1992 for that matter) I think Bush wins. 1988 really wasn't Clinton's year.