Are wrote:
If I skimmed properly (I apologize whether I did or didn't, as you've put in a lot of good work collecting all of the information!), it looks like you haven't taken the size bonuses/penalties for simply being a smaller/larger size into account; those mean the attack bonus for wild shaping into animals is almost always the same (except for Diminutive), since the extra STR gained for each higher size category is cancelled out by the size penalty to attacks.
Medium is +2 STR, no penalty, for a total of +1 to attacks.
Large is +4 STR, -1 size penalty, for a total of +1 to attacks.
Huge is +6 STR, -2 size penalty, for a total of +1 to attacks.
Similarly for taking smaller forms:
Small is no STR bonus, but with +1 size bonus, for a total of +1 to attacks.
Tiny is -2 STR, +2 size bonus, for a total of +1 to attacks.
Diminutive is the only wild-shape-applicable size that differs, with -4 STR and +4 size bonus, for a total of +2 to attacks.
The negatives are to DEX. Why on earth is that supposed to have any effect on the attack bonus? Please help me understand.
