Actually, I think it is time to give McCLIM a major overhaul, though I am not convinced anybody has the time.
Such an overhaul would start by correcting and supplementing the specification where it is wrong and/or incomplete. We might call the document obtained this way the CLIM 2.2 specification. It would be much more precise than the CLIM 2.0 specification, and we would make sure as much as possible that it does not have any contradictions.
From the CLIM 2.2 specification, chunks of the code base could be
refactored, checked, and selectively rewritten.
All of this, of course, requires more manpower, which we do not have.