I'm not a big stat guy but well done, those actually seem like meaningful stats. Unlike baseball I think football is really hard to judge by stats as so much is dependent upon what everyone else around you is doing or not doing right. Baseball is much more of an individual sport and as such easier to evaluate statistically.
No matter what you're looking at, it can be described statistically. The question becomes "how complicated is that statistic?" and, following from that, "do the metrics that we currently use adequately and meaningfully describe the event?"
In baseball, as you said, the answer is usually yes, because, offensively at least, interactions are very simple. Even in baseball, though, you used to hear all of the same things that you're saying about football when it came to measuring defensive performance. The too-simple metrics that were being used actually punished fielders who had lots of of range, and of course that was wrong. That wasn't because statistics can't measure defense, though; it was because they were measuring the wrong things. It was harder to do than a simple OBP calculation, and somehow people made the leap from there to conclude that it was impossible. It wasn't, though, as the last few years of innovation in this area have shown.
The same holds true for football. The issue isn't that stats can't describe it: it's that we've been using overly simplistic, altogether insignificant stats for far, far too long. We chose ease of compilation and use over actual relevant. Football Outsiders is one of a number of sources that are slowly changing that. It will be far harder to do effectively than baseball, and the end result won't be nearly as telling, but there are always extraordinarily insightful statistics out there to be found. In fact, I can all but guarantee that a lot of them have already been developed, but individual teams have them under lock and key. There's a reason why pretty much every pro sports franchise in the country has MIT nerds locked in the basement somewhere.
