In the DLC there should be at least 5 more maps, increase the level cap to 25 ( make sure it is harder to get to), 3 extra levels, some racing thing for buddies to play online (you know parkour style), and maybe 1 or 2 more primary weapons. Then you should put all of the patches on it and sell it normally at stores and online for 25 dollars and then pack it with the actual game for new comers
Why would they charge people who took trust in the company and bought the game before it came out, especially something as ridiculous as $25, and then just give it to the new people? DLC should never be as much as half the game unless you're adding at least a half more to the game.
I think if they did charge for what you're saying, $12-$15 would be more reasonable. It's not that hard to come up with 2 more weapons and 5 more maps. Plus the extra level cap would add variety for Dual specs and wouldn't really need new abilities added.