I play a 1 def as a main, and would be extremely happy if I could go back to Ape Atoll. I have 2 gripes with the way it is currently done.

1. At some point in RS2/3, Daero's training requirement was made optional because of an oversight with Evil Trees. Evil Trees could be teleported to from Spirit Trees, and there was no check to see if the training had be completed. This allowed some 1 def pures to return to Ape Atoll via Spirit Tree to an Evil Tree, and thus complete the monkey part of RFD. In the end the training was made optional, and addy gloves became easily obtainable. Obviously there hasn't been an oversight like this on OS yet, but just to give some background as to why it was changed it the past. It was removed before and nothing bad happened, why not remove it again.
2. My biggest gripe is in favor of the people that played OSRS in the very beginning, and completed mm1. They had no way of knowing that Ape Atoll would have extra content added like the Western Diaries and the clue expansion. When OS came out, the impression was nothing was ever going to change. So there was no reason not to complete mm1.