Swain's ult just feels bad, straight up.
I don't understand why they made the ult weaker while still putting it on a higher cd.
The damage, as is stands, sits at 35 / 50 / 65 (+ 14.167% AP) per second.
Compare that to pre-rework, with a far lower cooldown of 20 seconds, dealing 50 / 70 / 90 (+ 20% AP) damage per second.
While the heal, in comparison, isn't that much worse, contrasting the current 15 / 30 / 45 (+ 16% AP) to the pre-rework ult 20 / 30 / 40 (+ 12% AP), the real issue lies in how weak the minion healing is, too, essentially being from 3/6/9 instead of 8/11/13. doing this 3 times per second adds up.
And all that weakened effect for a 6 times the cooldown, which is at a static 120 sec cd.
The least that could be done, IMO, is to at least raise the minion healing and damage back to pre rework level.
I am aware of demonflare being a thing on top of it, but i think that the increased cd more than makes up for it. speaking of which, i really think that should go down a bit per ult level, too. maybe like 120/110/100 at the very least.