For me, I just hate how much Dark Arts spamming is now because of Siphon Strike and I hate The Blackest Night. Neither of them feel fun or satisfying to use at all any more. TBN turns out "use MP for more damage" mentality into a psuedo-defense-offense mindset which isn't fun to use at all. I think if TBN was a much longer cooldown I could tolerate it more, but wanting to feel like it has priority over Dark Arts isn't fun at all. I also feel very pressured about having to Dark Arts every Bloodspiller as well which takes a lot of the fun out of the Bloodgauge. Don't get me wrong, I loved DRK in 3.0 because of its difficulty and rewarding to master, but I don't think the mastery required in 4.0 DRK is satisfying or rewarding at all and it really killed the thematic reasons I played DRK.