Other than the three pieces of DLC coming in the next 12 months, the Season Pass carries a small bonus of extra collectables including – I believe – the missing five fusion upgrades.
I wanted to know from anyone that has the Season Pass: how far in to the story can the collectibles be found, and essentially if they will help in 1999 mode. I played through Hard slowly with only a couple trouble spots.
I'm excited to see more of this game, although I wonder if they can make the DLC relevant without feeling like a retcon, or missing chapters à la Assassin's Creed. I've had one positive season pass experience and that was with Battlefield 3.