The latest version of Satan doesn't seem as bad as before, perhaps evident by the number of people clearing it in under a minute. But for those without great weapons, magatamas or Ougis, it will still take a bit of time to clear. Following video is a simple guide on how to deal with Satan if you aren't going down the high damage route. The longer the battle, the more chances of making mistakes tho.

https://www.youtube.com/watch?v=b7_FxyxAg5Y

Satan's attack pattern seems to rely on your position. Depending on how far away you are after an attack, you can anticipate what the next attack will be. This enables you to dictate how the fight will go, making it possible to loop a pattern until you kill it.

I believe players with different weapon builds can certainly clear this faster, or any dungeons for that matter. But it does help that Satan is weak to Holy Element for this particular dungeon.

If it seemed like I was holding back a lot instead of attacking, that's because for the most part it was too risky to attack. Holy Pillar roots you to the spot while casting and the delay can kill me. Holy Light is worst so I don't use it for Satan. So try to pick fast casting skills when you're using other weapons.

Some relevant info:
Character level: 77
Build: MND Staff
Skills : Rank 5 Holy Pillar (on 2 staves)
Magatamas: 2 Kousei Magatama, 2 Nothingness Magatama (+500HP helps since my HP is so low)
Drinks used: Chidori, Moon King.

Some notes:
-I get some lag while playing, so you can see the timing is a bit off.
-The 0 exp results is because I have 2 Nothingness Mags permanently equipped.
-Moon King helps a lot. Having Ougi Rapid Storm on top of it is even better.
-Having 2 Holy Pillars on 1 staff would have saved me a lot of weapon switching.
-Oh, and stay away from the walls.

Btw as far as I believe he is not stunnable currently -_-

Thanks for the info Miyano. Stun reference removed.