Geez, everytime I'm about to get the "Win 5 Ratch Matches in a Row" trophy I get destroyed by someone way out of my league despite the fact that it's suppose to match me with people of my skill level. I hit a 4 winstreak, and then I fight a 9th Lord using Sentinel/Dante/Wesker. Got wrecked hard. Stupid, broken Custom Search...
Perhaps your excitement over getting the trophy is ruining your 5th match? Sometimes your brain fumbles when you need it most! I know that when I am learning a new combo, the first time I
almost succeed is the time I am guaranteed to drop it, because I get so hyped that I finally pulled the darn thing off.
I hate Dormammu's purification towers. They seem so superfluous. Slower startup and recovery than Dark hole, less damage, can't be used in the air, much harder hit confirm, fewer active frames. Only advantage is that they OTG and they have better advantage on hit.
I wish that they had half the damage and startup time, and could be done in the air instead of dark hole.
I've also changed my mind about Dormammu and fireball wars. His normals straight-up nullify projectiles, which pretty much changes everything about him.
First, I would scream like a little girl if Dormammu could use Purification in the air, but then that's probably all we would do with him in some matches, because it would be just that good.
I used to primarily use Dark Hole, but I have become a Purification convert. Yes, it's slower startup and less damage, but the damage difference is 1,900 on two moves that hit around 120,000 - it's not really a significant difference. Plus, as you said, a successful Purification guaranteed another Purification, even if it's blocked, so in practice it tends to be at least a 160,000 move. The startup difference is a whole 6 frames; less is nice, but it's not like the difference makes Purification bad.
More importantly, you said what Purification does when it hits, but what happens with Dark Hole? Unless you cancel into Chaotic Flame (don't all Dormammu players wish we had the meter for this every time), Dark Hole puts your opponent into a recoverable knockout. In other words, they can roll toward you and gain free distance, something Purification does not allow. At close ranges, Dark Hole can be an open invitation from you.
I don't know about you, but most of my opponents take to superjumping in on Dormammu. I rarely have people rush along the horizontal plane, because I have it covered by Sentinel Force already. If I didn't have Purification, I would just have to run from superjumps. Lastly, this is obviously a very minor bonus, but Purification incurs less damage scaling.