My ideas on that would be:
*Improving garbage collection without breaking compatibility.
there could be a client/CleanUnusedGraphics=0
on 0 it could work as default and on 1 it could also Unload assets when no used.
If that is too much there could be an experimental feature where player can manually remove assets from memory.
Like
var/sound/s=sound('MainTheme.ogg');
usr<<s;
UnloadAsset(s);
I don't know wether that would help an RPG but RTS games could really benefit. Personally I could split all main map animations with the unit sprites and level animations which if added all together I get a crash.