Hi all,
So with the Halloween sale I broke down and finally got an Excelsior, but one very odd thing is that the giant hangar bay at the back is completely open and it doesn't even look like that was fully modeled. Is that a glitch on my system or is this a common issue. Thanks!

It doesn't look fully detailed, but as for being wide open, that is how it was in the shows.

Actually it's not even the hangar bay as the diagram of the Enterprise B in Star Trek 7 showed.
It's a cargo bay whielt the shuttle bay is in the suace section.

http://johneaves.files.wordpress.com...e-bdd-copy.jpg

Yeah I believe it houses aft torpedo launchers and tractor beam emitters. Never understood why it was so wide open though... seemed to me like a waste of precious space.

In addition to the open and spacious cargo bays, the extra "impulse engines" on the edge of the saucer outboard of the main impulse engines were actually intended to be extra shuttlebays, according to the MFD's and ship designer Doug Drexler (which makes more sense if you look at the way the ship is laid out). Thank ILM for thinking the ship needs more glowy bits instead!

That may have been what they were intended to be but it's generally considered canon that they are additional impulse engines.
http://en.memory-alpha.org/wiki/Excelsior_class
So you should be arguing for the inclusion of saucer separation if anything :p especially once that becomes a console.