Why though? It seems like the right thing to do. If there's an orphaned package and people want to adopt it and become the new maintainer, they just make a new package. There can be infinite of the same package with slightly different names.

Take this example of solvespace. There are 3 different solvespace packages to choose from. The best one gets votes so people know what's on top.

source: https://aur.archlinux.org/packages?O=0&SeB=nd&K=solvespace&outdated=&SB=p&SO=d&PP=50&submit=Go

With the new change there are no surprise code changes from new maintainers, because that's not a thing that can happen. Previously, new maintainers could sneak in and push malware. People using the abandoned package should have to opt-in to new maintainers.