A Rune suggestion to encourage Mages to spec into Precision

Fleet Footwork is great and works really well on some mages. The problem is the attack speed and the entire legend line that even these niche mages just really don't want at all.

My proposed solution is this: Add a rune to either precision or sorcery that replaces bonus attack speed with (%AP increase = 30% of bonus attack speed, max 8%). After the 8% cap is reached all further bonus AS is just bonus AS.

This way the combination of Precision and Legend: Alacrity grants a total of +8% AP after stacking Alacrity (3% w/out Alacrity).

Thoughts?