While we know that Respawn already has new downloadable content that is being planned for the game, is seems unlikely that it will be only sold as individual download packs. EA has used the Season Pass many times before and has been very successful with it, so it would be unusual to see the publisher not go this direction.
One analyst tells us, “It is likely that Titanfall will have a Season Pass for the DLC, but right now Respawn is working with EA to get everything sorted for the launch and despite the fact that they are planning DLC, it might be too early know how much DLC they are planning or what the release schedule for the DLC might be. Look for this to be announced post launch when the first DLC pack is closer to release.”