I don't use squishy to heal MT's or OT's... I use the Tank windows... So I'm not worried about not catching a heal on a tank..
Also, I usually filter the list as well as sort it. In other words, it isn't raid wide cross healing, it's a subset.... either of some groups (Groups 1,2,3) or some classes..
It;s also not for just spamming flash heal. Who needs a shield the most other than a MT/OT? the person hurt the most. With a click casting addon, (clique, aceheal, etc), it's a two button affair, press a key to target the lowest, and then hold alt-rightclick (or whatever your particular key combination is for shield.)
There are many times a rogue, warlock, mage quickly takes aggro, and 1 second later is critical. It often takes another .5 second for the warrior taunt to happen to take aggro back, so getting that shield to the person who stole aggro as quickly as possible is critical.
For the sorting strategy I discussed above, it's a little faster to drop that shield with CT_RA than squishy.
I don't agree with the previous posters tone about "so becouse you dont like it sorting by hp lost no one else can get it ? stupid arguement tbh" this is someone's addon, and they will take it a direction they want. I'm a new user to squishy, and didn't realize this is a sore point for everyone. If the addon author doesn't want to add a parituclar feature, thats their perogative, and I'm okay with that.
We don't need to descend into a flamewar/pooslinging contest.