Thanks for the answer. In fact made some tests in the PTR and with very limited data (5 minutes solo fighting the dummy boss) I could see some changes:
1. A bit more dps (200-300 dps more) when using in the main hand Beserking and with black magic on offhand (comparing with beserking on both hands)
2. When analysing the logs, when using black magic the uptime of beserking was higher that when using 2x beserking in about 10-15% (of course this excludes the simultaneous/stack besrking buff)
Of course this data is very limited (I could have been just "lucky" with the crits on the 2nd try), and i can understand that black magic was "designed" for casters and not melee, but is nevertheless interesting to see this results. My
attention for the new black magic enchant was just because how haste is so higly rated on my enhsim EP calculations (arround 2.5EP). If you need the data just tell me and ill send it to you.