To throw my 2 cents into the Modern Sonic thing, I don't like the mod. I think it's too much, too many features, too different, and it doesn't work well with the levels as they are. However, I understand the appeal of playing as the Sonic that, at this point, a lot of players have grown up with. If you had an entire set of levels designed for Modern Sonic, great! That's an entirely new game, and if you want to make that then good luck to you.
That said, I think it would be neat if an extra character - maybe not Modern Sonic, maybe Neo Sonic, maybe something else - was included in the addons folder on install, but not loaded by default, as a way to teach players who poke around the menu how addons work. Right now when you install the game and you're not used to the idea of modding, it's just a button that shows some confusing UI and does nothing. Someone mentioned Egg Pack, that would definitely be a good option if the meme voice lines were taken out.