Would you guys think it would be better to have Gmod's addons organized? 
This 'menu' would be specifically for multiplayer which ties down any content pack to its designated server. It would only activate addons you would be using for the server that you join without any worry of conflicting addons from other servers. You could mark which addons would be for sandbox and multiplayer. The options would be "load this collection for this server" that could be enabled or disabled. I don't know about coding for Gmod but I think this would probably exist.

that'd probably be more intensive to switch between packs and also needing it to figure out what server's pack needed loaded

that vs just having all the addons u need cached + loaded

You think if the addons were connected to the server's IP it would be easier to switch between packs?