I tried Aion but dropped if after lvl 10 or so cause idk felt boring alone.
Same for Tera, Blade & Soul and Neverwinter..
Runescape (3) became too easy and has too many microtransactions, so if you look for a fun RS try a private server.
I did hear that a company was making a new MMO that would come this year.
The fun starts once you hit lvl 10 though for Aion and Tera. I recommend these two games btw.. Aion and Tera.. Tera more though.