RDM can still solo very well, but there's not much worth soloing that didn't exist back then. Most newer content focuses on killing mobs as fast as possible, and RDM is still horrible at speedy kills. It is still excellent at all other kinds of soloing though, anything that focuses survival over speedy kills, it's just not much related to new content. Some people solo NMs inside Abyssea for a challenge, but that's about all I can think of right now.

If you have some questions about content, can send me a /tell ingame, I'm also on Leviathan.