Would it be more effective to have one person work all the suggestions on a profile? Maybe, if that person had the experience and expertise to work all the suggestions.
Merge cleanup, born after parent's death, born before parent, etc., are suggestions that takes both. I know that i don't have the expertise to work a lot of those. I do work Merge Cleanups, but only tackle those when I have a fresh brain and plenty of time. Most of the other errors, like removing the USA, adding <ref coding, etc, are quick and easy. Those can be done while I have an extra five minute here and there.
Does it create more edits on an individual profile? Sure.
Is the work spread between us so that everyone can have a hand in improving our tree? Yep.
Data Doctors, like all the rest of us, are volunteers. They do what they can in the time they have. The Goal, at the end of the day, is to improve profiles. How we get there is just part of the process.