I think it's really silly to argue against "Pet mods". "Pet mod" is just another word for "Other metagame". The title of this forum is basically "Pet mods"; it's silly to say "we shouldn't have too many pet mods here".
From the sticky "Other Metagames Index"
3 Pokemon Tier
BW Cup
Balanced Hackmons
Clear Skies
Dream World OU
Glitchmons
GSC Redux
LC UU
Middle Cup
Monotype
NFE Metagame
Offstat
PU
Pure Hackmons
Random Battles
RBY Cup
Seasonal Ladder
Six Move Battling
Sketchmons
Tier 10
Tier Shift
None of these are pet mods. OM != Pet mods. They are a small minority.
"There will always be good mods and bad mods in OM."
All the mods are basically doing the same thing, despite each creator's quirks. No one is deliberately reducing metagame diversity; they are trying to expand it. Every team other than HO shouldn't have to carry SR. All five weather states should be equally viable. The spectrum of stall to HO should be equally viable. More pokemon should be viable. In fact, once a large enough number of playstyles are viable, perhaps there would be less need to flit from meta to meta; the finished product would remain eternally fresh. Another would be redundant.
Whatever differences may be asserted, I maintain that they are irrelevant while haunted by the specter of underpopulation. I don't care if hail is buffed by boosting ice defense or ice attack. I don't care if hazards are nerfed or spinners buffed. I don't even care if UUs are buffed via stat increases or other means. It's almost superfluous. I can look at how two mods do the same thing are argue for one or the other method, but it's a non issue if less than ten people are playing.
Now, considering the number of existing metas, I don't think we would have to worry about running out at a rate of one per month, even if we never revisit (I would be in favor of never highlighting the same meta within six months). At the discussion above, does the definition of mod matter for the purpose of Metagame of the Month? Why restrict to some definition of mod at all? Why couldn't LC UU get highlighted? It's not as if LC UU wouldn't benefit from it.
So why not just Metagame of the Month, everything in OM is eligible?