Ryan, yes there are a lot of factors. But .... going back two page example. Two pages of the same value. One has 3 outbound links, the other has 30. Clearly in most cases the page with 3 is better. In other words, if you have this situation 100 times, you might see it proving correct 70 or 80.
I doubt that figuring out several of the SEOmoz metrics is much (if at all) more difficult than the one I am describing, and a Link value would be of huge.
Every metric we see on reports is in fact a guess. PA, DA, Trust, Cblocks, Backlinks.. none can be completely trusted and we all use these tools with that understanding, and the hope that they are at least generally correct. What would be any different in a link value report that took as much into consideration as possible?
Can you imagine the time savings and efficiency acceleration of Link building if such a tool existed and was even somewhat accurate.
I think SEOmoz attempted this with the old Domain Juice passed metric. But seeing the formula for it, I can understand why they felt it was not very helpful.