On the surface of things this appears to be a simple and elegant solution, however you vastly overestimate the AI of this game, which is so insanely simple that your solution is rocket science in comparison.
Current AI:
1) Use revive/heal/dispel if appropriate (dead ally/low ally health/ally debuffs/enemy buffs)
2) Use offensive special if available
2) Use defensive special if available
3) Use basic
There is very little deviation from this for any toons. Programming in a specific routine to wait a turn if the taunter is faster than the enemy team would involve a lot of checks and stipulations in the code and would vastly complicate this very simple AI process.
Granted the AI in this game needs quite a lot of work but trying to shoe-horn in individual changes like this would only make it harder to make more important over-arching changes in the future.
What they really need to do is just change the numbers for speed secondaries - that is far simpler and easier than even touching the AI.
