It feels clunky, and sorta useless. 15 to 21 seconds is not long enough to enjoy melting an NPCs face while healing your friends. Because you constantly have to rebuff your friends. Was this done to balance PVP?
This makes the spec in my mind unenjoyable.
easy solution: baseline the azerite trait to make the 5 man heal apply 70% attonement instead of 60% duration, Solved.
Wasn’t atonement shorter prior to the patch?
How long do you feel it should be?
If you are attempting to keep atonement on the entire group you are doing it wrong.
I thought it was originally permanent. It’s been a few years since I played this class. Will be a few more before I try it again.
It’s never been permanent. DPS itself used to be a smartheal but that was removed a couple of expansions ago.
This is what OP is referring too and preferred. It was called atonement then too, but was a passive buff that causes dps to heal allies and I believe apply an absurd shield on crits.
It was a much more enjoyable playstyle, but was too strong on easier content where one disc priest’s heals and absorbs would steal all the healing.
Atonement was a passive buff back then so realistically it was permanent.
I say play what you enjoy. If you don’t dig disc then you certainly shouldn’t play it.
Debatable. 
I mean, I did say the DPS was a smart heal.
I know, and you are correct, but so is the OP - it was permanent as a passive buff until they made it a short duration buff.
Personally, I feel that 15 seconds is plenty of time and keeps the rotation rolling.
I agree. Based on their post, I assume they are trying to keep uptime on all members and that is neither needed nor desired. That’s the only way I can think that the timing wouldn’t be sufficient.
Disc is really fun, just set focus macros for your tank, makes the dps while refreshing atonements very easy
I don’t know why Disc even needs the annoyance of active Atonement when Havoc DH exists. They didn’t need this pointless complexity to be a functional spec in Mists of Pandaria.