If there was nothing cosmetic, why not have the pokemon be various blocks and shapes? How they look doesn't affect gameplay, right?

I agree though, they shouldn't be all season long. Just have them be occasional, and only in specific areas. For example: a snowstorm in north Kanto (from Pewter to Cerulean) that last a couple days, leaves snow on the ground for a couple more, then it melts and goes back to normal. At the very least we could have snow for Christmas.

See, I like that idea much better. I think it would be neat if like, as part of a Christmas event, we had snow for a few days. We wouldn't have to change all the maps, but just make it like rain effects or something. In other MMOs I've been in, there's been similar things. On Halloween, there were random pumpkins laying around, and on Christmas, there was a Santa event. One MMO that I spent a lot of time in actually had Christmas themed maps and dungeons and monsters.

Long story short, I like the idea of having snow as just a particle effect like rain for a few days out of the year. No more than that, though.

How about during the weather changes, different pokemon appear in the wild? That would be a cool thing to add on the game.

That would be an interesting twist, but I don't know if it'll ever make its way into a final version of POL. Correct me if I'm wrong, but I don't think that weather effects had any bearing on the appearance rates of Pokemon in the wild in the actual game, so I don't think it'll be included in POL. Although, for the record, I think that's a pretty neat idea!

Slippery slope fallacy; just because I'm saying that this particular thing is too cosmetic doesn't mean I believe that every gameplay aspect that's pretty is too cosmetic, or that we should take out everything that's pretty. I just mean that rather than focusing on something like that, it would be more beneficial to set up tournaments or other possible events for players. When you look at the amount of work that would have to go into it, you'd need an autumn, winter, summer, and spring tileset to use for every map that exists. If we were to add the other three regions, we'd have to redo all four regions four separate times. I'm sure you can see how this would be a waste of time, and something that isn't worth the effort we'd be putting in.

A few specific themed maps that are released for the holidays should really be the most effort that's given to an idea like this.

Agreed. That wouldn't be too hard, I don't think. I think it might be neat if we had like a Winter Town or something that was available only during a specific time in winter. It could be used for like, a specific winter quest or something. I dunno, that's just an idea.

First off, I agree that it would be better to have all the seasonal animation effects (leaves falling/snow/etc) only to happen occasionally during their respective seasons (maybe once every several hours or so, for a 10-20 min period maybe?). It definitely would get repetitive having the animation effects going nonstop all season long.

As for the idea having certain wild pokemon appear more commonly during certain seasons, that sounds like a pretty neat idea to. However, regarding the addition of temporary maps for certain seasons, it would be better, IMO, to have certain pokemon appear more commonly in the said map, based on how well they relate to the season the map is based on. For example, for a map that may be added just for the christmas season, maybe some pokemon that would usually be rare to encounter, like stantler/jynx/delibird,etc (can't say for sure that any of them will be rare normally), which could be considered christmas related pokemon, would be more common on the added map while it's there.

Just a suggestion, that sounds like realistically the most work that could be put into adding some kind of seasonal effects in the game. Just my 2 cents.