Hakkar is incredible easy, but of course you need to know what to do and that makes him easy. We haven't had much difficulties with Jindo either though.
However, we are stuck on Vael...(something) the Corrupt in BWL and have only moved onwards from him once (and made it through Broodlord??). Something about Vael. encounter just doesnt' like us. We even had him down to 1% one time when we wiped ... oh the agony.
Molten Core is farming now for us and we are trying to speed-run through it, which would be easier if we were decked out in epics (I only have 1 myself

), but we have done just over 3 hours now for an entier Molten Core run, which is pretty decent for a non-hardcore guild as ours with a healthy mixture between casuals (me) and more hardcore people.
Or next goal is to kill Raganos before he spawns children... was only 23% off last time.