Point taken on the tampering, accept it is an FFA directive.
My point for a hybrid Res/U23s (not straight Res) if your not playing 1st grade at U23 level are really much chop either. I think by making it straight U23s you are casting out guys who are of equal ability to those U23s (with abit more playing & life experience), and then filling those places with less talented U23s. Wouldn't it be more beneficial to have a blend of experienced overages guys (who can & want to still play at that level) playing with, & teaching some talented U23s who havn't made the top grade yet, then by making the them play along side less talent U23s (who will never play 1st grade) that they can just beat up on every week?
Maybe it is not as big a problem in the NBN comp but you see this at NEWFM level every week.
From my own experience of sports not so precious about age restrictions, and countless stories of bush youngsters going on to stardom playing along side men in lower grades at an earlier point in development is a much better way of equiping a young player for stepping into the top grades.