Advice & Help needed for 25m Heroic Garrosh

[Deleted]

Hello!

My guild is currently progressing on Garrosh Heroic 25m and I feel as raidleader that we are having
some issues. Personally I think it's mostly DPS wise, but I love to have another take on it from you
guys if you would be so kind to shine your light on it.

We currently have around 200 wipes on him with last sunday getting to Phase 3 finally.

Logs for this raid: http://www.worldoflogs.com/reports/rt-t3p80hqeh156550c/
For this raid Shadowpriests(Selador & Sloefke) and Badtoady were on Siege Engineer.

Last night however we had a bit different setup for progress on him and
didn't even get deep into Phase 2 (or Phase 2,5 after 2nd intermission).

Log for yesterday's raid: http://www.worldoflogs.com/reports/rt-c9sr5js5ejkvkixh/
For this raid we had our Locks most of the time on Siege Engineer with our Shadowspriest Selador.

Is it a really a DPS issue we have (overall raid ilvl is 576) or is it something else?
Movie of our best attempt so far: https://www.youtube.com/watch?v=hG1_...Rwa4kFSmE3YTAw

Thank you already for your time if you pass your advice & tips!

Greetings!