Some questions...

Wis - seems to have the same problem as dex. Max elf wis is 21 since they can't allocate. Human w/ prime wis is still only 23. I'd suggest applying the +2/+1 rule, except then there's virtually no reason to ever choose wis as a prime stat.

Dex - Am I right to assume the +2/+1 thing doesn't apply to half-drow since max drow dex is 24?