I've tried around 6 or 7 of the most populated Pixelmon servers and I've been highly disappointed with them. For the most part it goes like this:
I log in, am given some commands to use, usually /kit starter or something to get me started. (This is fine)
I am told if I vote for the server I get some kind of in-game compensation (This too is fine, as long as it is supplementary and a relatively small reward)
I am told I can donate to the server, and a bunch of benefits come with donating, usually at different tier levels (This I usually have a high tolerance for. I understand servers don't usually pay for themselves, and am grateful that someone else is willing to shell their money out to help keep it running, because I'm not)
Then after I finally get through all of the initial chat notifications/ finish reading all the signs in spawn, I am about ready to play the game. And usually, within the first 10-15 minutes of logging into the server, I end up logging out and deleting the server from my multiplayer listing. Why, you ask?
Maybe it was seeing 3-4 copies of the same "Legendary" Pokemon being owned by every other trainer as if they were pidgeys.
Maybe it was the 40 warps to every biome, pokecenter, shop and trade location in the map, so you could effectively play the game without leaving the chat box.
Or maybe, it was the fact that almost every aspect of the game was made readily available through a menu. You can buy little keys and open chests that give out rare pokemon and shinies like candy. For an increased price, you can spend real money through in-game transactions to directly buy any Pokemon/item that would ordinarily take a great deal of effort to acquire. (This is where it becomes a problem, and is no longer just a "donation")
For what ever reason, these highly populated servers take away any sense of accomplishment from the game and monetize every aspect. Why bother going through the effort to acquire anything when it can be acquired with 0 effort by someone else? One of the main selling points of the Pokemon franchise is to go out and capture these pokemon, not buy them from a menu. And I'm not talking about buying pokemon that someone else actively went out and caught to sell on a GTS, I mean the ones that just spawn into existence when purchased.
I want to play on a server that gives me my starter, a hand full of pokeballs, points me in the direction of the nearest biome and simply says, "Good luck."
A server with a real economy, and purchasable pokemon/items that people actively spent their time finding/making to turn a profit.
It doesn't have to be a "Vanilla" server. It just can't be this modern scripted to hell garbage you see on every minecraft server.
It's sad that most of the servers that somewhat resemble a good experience, are barely inhabited. If anyone knows of some servers that don't spoon feed/ over-saturate the game with artificial, micro-transaction pokemon/items, feel free to let me know.