Erpy: XSeed went above and beyond the call of duty with this one and added 5000 additional lines to the game's voiceover,(since the original Japanese actor for the main character was kind of expensive, many of his lines aren't voiced in the console games) making this one too the definite version of the game.
And yeah, since XSeed themselves seem heavily involved with the port, it's all but officially confirmed that these'll be on GOG too.
Note that these games do have DLC (unlike the Trails in the Sky games), but most of them are simply alternative clothes that make no difference to the gameplay.
Oh, that's right -- forgot about the DLC. Well, however minor, I wouldn't be surprised if they just threw it in with the base game; especially given how above and beyond they're going with everything else here.
The whole thing is just awesome, though -- I'd put Cold Steel up there with my favorite RPGs I've ever played, and now they're just making them both that much better.
(and replaying them, and tackling The 3rd should make the wait for CSIII or the Crossbell stuff at least a little easier.)