It will keep our candidates in the news, while there will be less of a reason to cover what McCain is doing.
The Iowa Democratic gubernatorial primary in 2006 was hard-fought and didn't end until June, while Republicans coalesced around Jim Nussle early. It didn't hurt our candidate.
I think tough primaries sharpen our candidates' skills.
What's disastrous to my mind is if the decision about seating FL and MI decides the nomination for us. That would lead to lasting ill will, no matter how it was resolved.