PEBA does have rules allowing CPs to be spent on park improvements such as increased seating capacity, altered dimensions and relocation. The
GUBA's system was actually part of the inspiration for that; they indeed have a very thorough park maintenance system that takes a great deal of factors into account. I love the way their system is setup. However, I don't think such a system would work as well with my group; I fear it might be a bit too much overhead for some of the owners. Guess that's where it's important to know what you're working with.
Recte44, may I ask why you'd recommend against editing player ratings? We're currently allowing owners to use CPs for a one-time improvement to player ratings, so I'd be very interested to hear why this might be a bad idea.