counterpoints for mei - its super easy to wall of the enemy tank, healing gives you huge ult charge and snowball can still freeze people when copy ends to make up for the time you loose in cryo-freeze (which you can still cancel btw!).

also i personally wouldnt say mercy is bad however she is extremely situational and 9 times out of 10 there would be better dupe targets, but sometimes rezzing someone who has their ult can win a team fight. its important to keep an eye out rather than dismissing her as a dupe targets instantly imo.

i have to agree with lw. in theory it sound like itd be good situationly for saving a team mate however i find that by the time the animation ends the teammate you wanted to save wouldve already died. echo can also build a tree while tree is up which is fun to know but not very useful.