this may have been suggested before. simply put:
could all big packages, say over 20MB, have a dependency included in them for $pkgname-fixes, which would be stored in the fixes repo. this package would essential be empty for new releases but if a package needs minor corrections - e.g. adding a : in a script - it is not easier to have this include in a tiny package rather than update the whole package?
we would be talking about very few packages that this would actually apply to and it would have to be preemptive - i.e. the dependency would have to be there (it may not even need to be a dep) before any probs occur but if this turns out to be an evolving fix pacman would still keep up with the changes.
like i said - prolly already been suggested an does not exist so prolly, therefore, a bad idea that is anti-the arch ethos. but i thought i would suggest it