Why don't any of the SHA-256 vulnerabilities matter for mining? Wikipedia lists several vulnerabilities in SHA-256. Presumably, none of them can be used to mine faster, or it would be done already. Why don't these vulnerabilities lead to a problem for mining?
The attacks are against a "poor man's" version of SHA-256, where less rounds are performed than in the real SHA-256. They are useless for breaking SHA-256 itself, and more so for the double SHA-256 used in Bitcoin mining.

Also, what would be most useful for mining is a preimage attack, and those are much harder than collision attacks. You can see in the table on Wikipedia that the proposed preimage attacks, though faster than pure brute force, are still impossibly complex.