I think it would be really interesting to look into this possibility?
Of course, if you change or add something, you would have to inform the players of your server..
But the same goes for any other Forge server if you add a server based mod (sorry, I always get plugin and mod mixed up and a friend told me that mods are always plugins if you talk about servers). Then You would also have to say: „Hey, I added Pams Harvest Craft etc. please add this to your mod downloads.“ and compatibility is also very similar for forge: if you play a minecraft world 1.7.10, you can only download mods that have a version for that. And if mods are incompatible - well, that can theoretically also happen if you cook together a bunch of mods in forge?
maybe you could forward the idea/think about? Thank you anyhow!
If removal of a mod/plugin is too complicated, you could add a warning, that you cannot remove it. Or how do you solve that problem for forge server? Where there are surely also people adding and deleting mods/plugins as they play?
edit to add: in my case especially- life in the Woods- the version is stuck to 1.7.10. I couldn’t update any of it- unlike Feed The Beast or Tekkit- because a lot of the mods used (Antique Atlas etc.) don’t have a more recent version. The last update for the launcher happened in 2017, so TL;DR: a life in the woods player can’t and won’t update any of the mods/plugins Used. So maybe this feature could be a unique thing for LitW or other modpack that aren’t updated any longer or you could „lock“ updates for those, if it gets too complicated.
Just my two cents as ideas?