The RMGN debacle is evidence of what bad can come from convention.

Special interests will own the delegates, particularly since the Dems are sitting on the reform Marty Knollenberg proposed in Oct. 2007 that I pointed out to him last year.  The Michigan Campaign Finance Act of 1977 forgot - understandably due to the rareness of conventions - to include delegates in reporting category defintions.  And limit definitions.

Democrats - I'm calling Ward Connerly if there's a convention and there no law to say he can't give me one giant donation, which I'd never have to report.  And I will run if there is a Con-Con, despite my hatred for it - largely to protect MCRI, but also to protect the initiative process, Headlee, and all that the people have earned in the last 40 years in at least marginally checking government excess.

Republicans - Stryker nightmare.

It's not individual candidates that evade the radar - its the potential for competing blocs of "sponsored" candidates.  A Herculean battle would occur.

You think the raw costs of a convention in terms of administrative costs, staff, space, etc. are high.  The political costs, and the subtle changes that can only ultimately favor the elite power interests since they are best positioned, are huge.