Really I love JA, but I just don't have much time to play it anymore. I help run a popular server and play it once in a blue moon now, but mods are really what keep it going for me. Mods like the OJP (Open Jedi Project), Endor Siege, Asteroids Mod, bonus maps, and things like that. Without mods I probably would have stopped playing the game for good in '04.
And no, we have NOTHING official or unofficial about a sequel to JA. Just like with Republic Commando, every month or so somebody will ask if there's a sequel, but nothing ever comes of it, period. Just like every so often somebody starts a rumor that the servers for JA are all shutting down by X or Y date, nothing ever comes of it. If we knew something, we'd be talking about it, really.
If you enjoyed the multiplayer of JK2/JA, then Battlefront 2 will annoy you no end. It feels scaled back and the graphics feel more cartoony. It has quantity, no doubt, with the multitude of vehicles, but it lacks (IMHO) the quality that JK2/JA had.
The Jedi are crappy and used soley as powerups, and the vehicles are clumsy and slow or fast and fragile as a balsa-wood airplane. It might be a fun game, but it's nothing like these.
There really is no true sequel to the JK series out there beyond JA, but if you haven't already, check out the previous games in the series. The graphics may be dated and they may lack dedicated servers, but the gameplay rocks and there's hundreds if not thousands of mods to check out free. ;)
As for the recent Star Wars games, Republic Commando is great, but you'll beat it in about a day or two, and the multiplayer you'll get tired of in about a week.
KOTOR and KOTOR 2 come highly recommended, but I haven't had the time to play them. Be warned that the combat is turn based. There is some modding for the game apparently, so that might be worth checking out. No multiplayer of course, so once you beat the game on each side of the force that's about it.
I'm not one for pay to play MMORPG's, like SWG, so I can't recommend it. Many people I've talked to say it was a disappointment, and now the game has been drastically dumbed down for noob players. It looks to me like you have to buy the expansion packs to really get the true Star Wars feel, but that's again the opinion of one who's never played it and only read about it or talked to former players.
Empire at War looks promising, but that's a whole different genre (3-D RTS, apparently in the same vein as Emperor: Battle for Dune). It won't be out until next month last I heard.
As for the Star Wars console games, Rogue Squadron III is pretty cool, though only for Gamecube, and the Episode III game is heavily overhyped, apparently only considered good by fanboys and people who haven't played the PC version of Jedi Academy and seen what that kind of game should really be like (or just people who will buy anything Star Wars related and not care about gameplay).
When checking out old games, try also the X-Wing series, especially X-Wing Alliance. Very cool, and there's many mods to enhance the graphics and ships to make them more realistic to the movies (
www.xwaupgrade.com)