The whole point of a season pass is that you don't have to worry about tracking DLC, it will just come to you. Games like Forza and Driveclub have added a lot of value in their Season Passes (at least 6 months of DLC post-release, with a big price reduction over buying all of the DLC separately), so that's my benchmark.
Don't get me wrong, I like SLRE for what it does deliver, and I went into this knowing full well that Milestone are not big on post-release updates. I was just surprised by how minimal the Season Pass content appears to be, and that all of it appears to be ready at launch.