Why I am glad Trump didn't win Iowa (They have a crummy record of picking the GOP winner)

Iowa picked Santorum in 2012 and Huckabee in 2008. 

4. The caucuses have a poor track record of predicting the Republican nominee

In stark contrast, the Iowa Republican caucuses have a remarkably poor track record.
Since 1980, Iowa Republicans have accurately predicted the GOP nominee only twice: Bob Dole in 1996 and George W. Bush in 2000. In every other caucus, Iowa Republicans chose candidates that flopped outside Iowa.
Why are Iowa Republicans so far out of step with the rest of the country?
The answer is that Iowa Republicans are much more culturally conservative than the national average. Iowa GOP voters have consistently chosen polarizing, socially conservative presidential candidates over more electable establishment candidates.
For example, in 2008, the far-right social conservative candidate Mike Huckabee beat John McCain in Iowa. In 2012,  Rick Santorum, a Republican even more conservative than Huckabee, defeated Mitt Romney. But neither Huckabee nor Santorum received a lasting boost from winning Iowa, and both campaigns fell far short of winning the GOP nomination.