For fleeting expertise and toggle ability this is how I see it. A naked Messa's peascemaker cost 25 on activation then a solid 15/s. With the "old" maxed fleeting expertise (+60% eficacity -60% duration) it cost 10 on activation and then 6/s. Now with the "new" fleeting expertise the activation cost will remain at 10 but the chaneling cost will stay at 15/s. But fleeting expertise will remain useful even for toggle ability ! If we add continuity to the build it will become : (15/0.7)*0.4=8.57/s, much better. While a naked continuity will only be 15/1.3=11,54/s. So according to that, fleeting expertise will remain useful for toggled ability, we will just have to keep in mind to increase the duration as well. Sorry for potatoes english.