Actually, it is not uncommon for that to happen somewhat. 40-man
means you have to watch your positioning quite carefully during
Phase II or else you guys will enjoy continuous Deep Breathe
spams.
30-man spacing is a lot easier.
Honestly, it is always more fun to have a boss encounter go awry
and then try to salvage it. This happened during our last Nef kill.
Everyone was semi slacking and when about half the raid died
(mainly the DPS portion), everyone suddenly sat up and
concentrated. Of course, we killed Nef, but it was nothing like the
usual.
Also, note that the mod Decursive will no longer be functional
after the next patch. My guild spent time practicing to work
without Decursive over last week's raid. Boy, was Chromaggus tiring
without Decursive.