What kind of latency were you playing on?
I got to do Karazhan with a different group recently and had horrible lag on the etherals and Netherspite, I think it was something to do with all the debuffs present.
I was one of the tanks for Netherspite and the lag wiped us, I couldn't tell what I was doing and when I looked at the combat log afterwards I had a lot of those type of errors.
Before the pull my ping was my standard 600ms, not sure about during the fight as it was a slide show.
I think it is UI lag which stops you queuing up the next Maul, I haven't tried a macro with /stopcasting in it yet but it might be worth a shot even though it should be unneeded.

While on the topic of queuing up Maul does anyone else find you have to press the button twice to get it to light up?
I get this all the time and asked a mate if he has the same problem with Heroic Strike, he doesn't but commented that he had noticed the same thing on his druid.

Such is the nature of balance in PvP -- I'm quite willing to live with never being quite able to click that flag to return it personally; it may be frustrating at times but I'd rather not lose the additional benefit that being able to swap forms on the fly gives me.

Win some, lose some...

Wondering if the fact the S is capitalised in castSequence would make it break - I've heard of stupider things and macros are quite caps-dependant in my experience.

I'm really starting to have some itemisation concerns about feral gear.

On our guild forums most people keep a "wishlist" of gear they would like to obtain in the future. It's pretty depressing to see some classes with a list of gear where they can obtain two or more upgrades in most slots from their t4/5 gear currently, when my wishlist contains maybe three items total, one of which is the crafted belt (still not dropped for us, 3 clears of SSC/TK since patch with one other guild having it on the server who aren't selling yet), on top of the tier sets.

It's annoying when you look at say, DPS warrior shoulders, and find that theres shoulders off Rage Winterchill, plans for haste shoulders from BT, shoulders from both Kazzak and Hydross, and then t4, 5 and 6 sets. Then look at say, druid bracers, and find that theres not a single set of bracers from any raid boss/instance in TBC with more than 1 strength on them. There's 3 sets of rogue bracers (Teron Gorefiend, Rage Winterchill and the haste crafted set off trash) of which only one is really "suitable" for druids, and even then isn't really that perfectly itemised.

It pains me to need to PvP to get the bracers and gladiators maul because there isn't another item that comes close from PvE for those slots - I wouldn't mind if they were best by a small amount, but when there's no alternative I really wonder if Blizzard just forgot about non-set itemisation for ferals post-t5 (the only non-set items I can find are the treads of the den mother, and the pillar of ferocity, from 14 bosses in Hyjal and TK, and one of those drops is from trash). I also wonder why there are a number of two handed DPS weapons from Hyjal/BT (serving two handed DPS warriors, ret paladins and possibly hunters as a secondary weapon), and only one or two caster weapons (serving all warlocks/mages, spriests, eleshamans and boomkins). Seems a bit stupid itemisation-wise to me.

/rant.