Doc! I have to admit that I smile when I think that not only have you happily adopted bluray, but are also praising Audyssey technology, if in a somewhat muted manner due to compromises. I swear it seemed at times that you avidly hated these technologies, lol.
Anyways, I would like to share a couple of things that may or may not help someone be more educated about this stuff.
Marantz has never used the highest consumer EQ from Audyssey, the XT version. According to their website, XT can have up to eight times the satellite resolution of the regular MultEQ (which is what the 8003 sports).
If one had access to a Audyssey Pro capable unit, then the satellite filter resolution can be up to 16x greater than MultEQ. These are almost uniquely with pre/pros (All Integra/Onkyo, Denon, NAD T175). I think* the only receiver with this capability is the Denon 5308.
I believe the pro kit costs in the ballpark of $500-600. I actually asked if I could possibly join a training class, but I'm not allowed as I have to be a pro CI, or something, to be accepted. Still, many non-pros have done this. I bet for someone like you, it would be pretty easy. My own unit is not Pro capable anyways, but I did consider upgrading just for that at times (there was once a sale on the Integra 9.8 for only $600 or so).
Finally, and I don't know how you do it with Marantz, you should* have more than one target curve available, at least if going by what other manufacturers have. (Then again, I only really paid attention to XT units.) There is probably the house Audyssey curve (with HF rolloff), and the Flat curve. Historically, Denon was superior to Onkyo as far as the flexibility of choosing either curve based upon listening mode (particularly stereo). NAD goes further by adding a third curve as designed by Paul Barton (PSB).
Cheers!