RSC was never really finished properly for endgame, many skills dont have benefits for higher levels. I remember they planned player housing and probably full dragon gear too but unfortunately those plans instead went into RS2.

I think the housing is a ridiculous idea but dragon gear would be cool right?

We could have some kind of endgame dungeon where you can loot super low drop chance dragon ore or bars that you are able to work into gear with increasingly challenging skill levels of smithing, crafting etc. just like dragon sq at 60 smithing after Legends quest.

Just throwing an idea on the table, I have no idea if the devs want custom content towards the end.