Well, not necessarily "experts." But Dan Bartlett, former consigliere to President Bush, holds that opinion of Fred and voiced it in a recent speech to the U.S. Chamber of Commerce. From the WaPo:
Thompson, Bartlett said, was the "biggest dud" because he peaked last spring when he first started talking about running and since then has yet to articulate a compelling vision for why he is running. "The biggest liability was whether he had the first in the belly to run for office in the first place and be president," Bartlett said. "So what does he do? He waits four months, fires a bunch of staff, has a big staff turnover, has a lot of backbiting, comes out with his big campaign launch and gives a very incoherent and not very concise stump speech for why he's running for president."
Actually, Bartlett offered up harsh assessments of virtually every GOP presidential candidate save for Rudy.