I think that kaioken attack speed need to be increased only by 5% more. By this way Kaio gives you a +10% attack speed at max (a half that given before the nerfed update). This would be suficient.
Other way (a little OP depends how you look) is to increase attack speed by 5% for extra kaio that you use (x1= 5%, x2=10%, x3=15% ,x4= 20% and x5= 25%) because for 1grade you use the drain LP is enormous but with a healer you will be able to use (by this way you be able to use high speed but in less time until you LP be consumed).
I'm a player with a poko and karma in DBO TW and current DBO.