Golden Sun is the fucking shit, and The Lost Age is more of what you love, just better. The only reason you might not like The Lost Age is because you start playing as different characters as well.
Honestly, I loved the gameplay of Golden Sun, it has a lot in common with my second favorite game of all time, Skies of Arcadia (fast paced combat, along with a good amount of puzzle-oriented dungeons). You'll want to play Lost Age if you enjoy the story as well as the gameplay, the story in Lost Age felt absolutely epic IMO.
Currently playing: Uncharted: Drake's Fortune, NBA2k11, Metal Gear Solid, Picross 3d