Using a JA for fastcast is very counter productive, and DE is a great asset right now and will only get better after the update.
Depends if the fastcast works on recast too, then it'll be worth using on Dread Spikes among other things.
The changes to group 2 merits aren't the only thing to consider here, but also Relic +2aug pieces that work with them.
You can also cast in Relic +2aug head for +10% duration per DS merit, which is huge
on either Dread Spikes or Drain II's HP bonus, so 4/5 or even 5/5 DS is very worthwhile once you have +2aug head (and I believe you only have to use DS with it on, don't have to cast in it, so lose no DMS, but you'll also get the -8% casting time if you precast in it too).
The sweet spot for Diabolic eye, 80~85% hitrate, shouldn't be happening. You should be switching gear for that amount before relying on a JA only up 60% of the time. The answer to T6 Jeuno is to stop being a BNS whore and eat some goddamn Pizza instead of Buns (because Taint has Apoc, anyone without is gonna be even further behind Diabolic Eye being enough). The only thing Diabolic Eye gets from +2aug is +6 seconds per merit.
Muted Soul may still be a joke, but the +2aug for it gives 3% Zanshin per merit with Souleater active. 4/5 gives about 1.7% at 95% acc more hitrate with that 12% Zanshin, 2.5%at 80% acc, just for comparison not as an endorsement.
So assuming you want to keep 1/5 DS always:
5/5 DS: +50% Dread Spikes or Drain II duration every 5 minutes, -50% casting time but on top of 1 second of JA delay. Note that this does negate Hasso/Seigan's penalty if you want Dread Spikes up in a hurry and works on top of the -8% Black Magic Fast Cast if you precast your +2aug head too.
4/5 DE: +20 Accuracy (10% hitrate) for <1% of the content currently in the game but only for 204 out of 300 seconds or 68% uptime
4/5 MS: -40% enmity generation with Souleater active (you'll probably still outpace every other DD if you open with Souleater), at least +1.7% hitrate on everything
(even at capped accuracy) but only 20% uptime (again, Souleater active).
DS has real implications for lowman DRK tanking if you use it on Dread Spikes, but also for the extra duration on Drain II's HP bonus (+50% if you 5/5) for zerg output. With perma-5min Dark Seal now in sync with Nether Void, 5/5 is very
viable for both tanking and DD roles!
DE has no real breadth in scope of usefulness. It's only up 68% of the time on less than 1% of the mobs in the game and easily replaced by making better decisions about gearing and food.
lolMutedSoul is as useless as ever, even combined with lolZanshin.
5/5 DS with +2aug head looks to be the only choice to me. Edited, Feb 7th 2012 8:44am by Raelix