1. Since when does Discovery extend SP? I might not be up to date but to my knowledge that’s not really a key feature of the mod.
2. For people wanting to play SP there are plenty of mods at moddb which despite the changes and additions still allow to play the vanilla storyline. To my knowledge there are three mods extending the FL storyline. Crossfire, Nomad Legacy and another which name I currently don’t remember but know that it can be found at moddb.
3. You might not like certain other mods (for whatever reasons) but generally your personal opinion might not be the deciding factor for other players out there. Is it such a terrible idea to point players into the direction where they can find all the mods and make their OWN decision about what they like to play?

Really…