While it is nice to see rare monthly pets every once in a while and I can see, that it's interesting in some regards, I have to say, I would prefer this to remain something special, not something regularly expected.
Another reason, I'd not like to see this is that releasing them more often would make trading even more stressful than it already is. To be honest it could be quite a pain to even trade for pets that pre-rarity update turned out to be -just- uncommen, because people were seeing it requested a lot and assumed it might turn out rare. I think this effect would only increase with more rare monthly pets. The few pets that did turn out rare in the past weren't particularly fun to trade for, to say the least. Having this happen all the time I think as a consequence I would just lose interest in completing monthly litters.
I also want to mention events, which intensify trading each time and where a lot of rarer pets can be obtained, which in my opinion is the best option for new players to start collecting them for themselves and to trade with. While I do enjoy events, I also appreciate the times between them with a bit of a break from the frenzy.
In general I feel like the focus is too much on rarity altogether. There are so many amazing little artworks and some of them are omgsc - common, yet they are treated like junk, because of rarity. Same thing with date taken into consideration: some fairly unspectacular pets are being considered much more valuable than some amazing linearts of the same rarity, simply because they're older.



















