It was entire alternate playthrough with a female main character, new characters to build social links with, and a lot of new insights into the other characters of the game. The characters you fight with have different relationships with the female MC than the male MC. The PSP version had both playthroughs on one disc, though they had to make some adjustments like turning it into more of a visual novel style than 3d environments for the “town” segments of the game.
This is where I feel modders could get a very decent final say.
There will definitely be enough material to TTS the dialogues that don’t exist in Relaod, and the text, sprites and models already exist spread between p3p, the rhythm game, etc.
I’d wager it’s pretty doable to mod the content into the game once it’s out.