Personally I don't think anything should be done about the AP It seems to me like that system kinda regulates itself already. If the AP gets stale--due to walls of the same breed, due to high time stamps, or for any other reason--it will start moving more actively as timers get lower. In general, special events like Holidays aside, I don't think the regular AP even ever gets below influenceable timers (the critical threshold which would make eggs even less wanted, let's say) no matter its content, with all its single-breed walls and stuff. But as timers get below 5 days, especially below 4 days, demand for eggs grows no matter what they are, and eventually they'll be picked up in a timely manner. In other words, effectively eggs in the AP, no matter their breeds and lineages, gradually grow in demand as long as timers get lower and not higher. So where's the problem?
If a player doesn't like what they see in the AP, they can either keep hunting if they wanna spend more time on that or simply switch to something else, on DC or outside it.
The AP doesn't have to cater to some specific player's/players' needs and wants, no matter how popular or unpopular. It doesn't have to be pretty, varied or interesting in any way, that doesn't even seem to be part of its design tbh...
(And no, I don't believe that players who mass-breed stuff actually get any exclusive "gains" from their activity and walls in terms of gameplay, regardless of their intentions, emotions etc.: it's not like you can catch anything you abandoned yourself, plus there are scroll limits even if stuff gets reabandoned so the thousands eggs bred are of no use to them personally, aaand the lower timers the AP gets pushed down to as a result of some walls benefits those specific players no more than the rest of the community!)
Anyway, the AP is just a wall of eggs that were tossed away by players for absolutely any reason, displayed in chronological order. I don't like the idea of making it more complex than it currently is, and artificially "fixing" it in one way or another to make it (subjectively!!) "better", thus getting rid of its neutrality. And yeah, just in case, personally I don't mass-breed anything (heck, I don't breed much at all even for myself) and I do find monobreed walls annoying! But the idea of changing the current nature of the AP rubs me the wrong way. IMO the AP doesn't have a real problem worthy of intervention and should be kept as it is