I tried to keep a brave face on, and have done so for quite a long time. Plowing through 85 or so CE monsters against the thunder worm was not exactly fun. But, at least I could play them as knowing what they were getting into and not attempt futile tactics. Now, I have to spend time and effort on creatures and try not to metagame knowing they are freakin' useless. The Styx dragon was the last straw. I tried not to metagame, I had him come back out from the ground, but that really just sucks.
What makes matters worse is that I know all Greybar has to do is have the elemental fight the dragon while the planetar does nothing but fill the eastern edge with a few more blade barriers. Who wants to start off each combat running through 4 blade barriers? How is that fun for anyone, including Greybar? How does it in any way help with the purpose of the BoAA knowing it won't be fun?
As for the burrowing thing, I don't know what the answer is. It's just irritating as hell to have monster-after-monster come in with great melee abilities and zero ranged abilities, and be completely useless. And then there are creatures like Meineke that just makes things suck. 80+ damage per round in which there is no way to negate it? Who has a +20 reflex save just to have a 50% chance or so to take half damage? Who has a 20 caster level to overcome SR only half the time?
It's just not fun, but I have no answer. We instituted the chicken draw rule to avoid a similar 'not fun' feeling on the other end of the spectrum. I'm sure Greybar would be extremely irritated to have one of his best monsters take a draw (albeit VERY under-CR'd monster -- I mean, really, a 17th level cleric is CR17, why when you had the HUGE number of additional abilities of the planetar the CR drops?).
My feelings on this, btw, has nothing to do with anyone here. I think everyone here does a superb job on all aspects of the battle, but all of the current fights in Elysium and Celestia are frustrating and have been for a very long time, going back even to CE vs. N. I am not forgetting what I'm sure was similar frustration for PJSlavner against CN or ugulu against N and then CG.
The CR disparity and then what basically amounts to a supreme EL disadvantage (advantageous/disadvantageous terrain) is a big damper. I can handle losing, I think I've proven that, but the frustration and irritation finally got to me.