I don't know, Sundulous. I tend to forget the specifics of level design rather quickly, and since I only played the DS version, the game and its locales certainly looked different to me. There is certainly rehashing of battles imo, though, so if you played FFIV twice recently, maybe wait a bit before downloading The After Years.
The gameplay is very similar, though it has poorly-implemented, confusing team-attacks which I barely use). That said, I have enjoyed the first part (800) and Rydia's Tale (300) so far. The somewhat constrained party members at your disposal make Rydia's Tale fairly interesting, actually.