Personally I see Alacrity as a useful stat for sage healing, tho trying to find the right amount of it yet, because I see Deliverance as being a great spell for tank healing in combination of rejuv and healing trance. Salvation I use on healer/rdps mainly. (great for Noble Sacrifice for Force) From my understanding sages want there Alac somewhere around 8.9-9.3%, tho I can't seem to get it in that range myself. If i remove 1 Alac enhancement i go from 10.07% down to 8.7% which i'm reluctant to go that low on. I've alrdy hit my surge cap of 75% so it really is a minor difference.
Saying "surge cap of 75%" is misleading because in my gear I have over 80% surge.