Peter - I agree with Tubegroover that some audiophiles want a certain sound and others are more into the musical experience. I lean towards the musical experience where the sound is as if I'm in the jazz club or else the performers are in my room. Initially I thought that imaging was the most important factor for the "in-room" experience. As I've progressed on the upgrade path, I realize that sound characteristics such as tonal accuracy, micro-detail, dynamic range, lack of noise, etc. are as important as imaging in the illusion of reality.
While my experience and the quality of my system is not near many of the others on this site, I'd like to give a few examples of what I've found. The addition of a tube pre-amp improved imaging tremendously but seemingly more important was the "black" backgound cause by the absense of noise. Upgrading the amp also improved imaging but seemingly because of tighter bass (I'd read about this but experiencing was something else). Upgrading the cd player added stunning detail (Arcam Alpha 9, similar to your FMJ). All of these increased the brightness to unacceptable levels so I upgraded to NOS tubes which now provide the spaciousness, depth and liquidity. It's been a fun process, with more left to go.
During this whole time I've kept the same speakers and relatively constant speaker positioning. This is not to say that speakers and positioning are unimportant. To the contrary, I like to think that I'm saving the best for last. Speaker positioning will always be limited in this room to due the constraints of reality however I pull them out from the wall and play with placement for serious listening sessions.
I have a few recommendations for you. IMHO, your cd players and speakers should be capable of giving good imaging. Although the Classe amp is well regarded, I'd play with tubes. You can buy a tubed integrated with NOS tubes here on Audiogon and then sell either the Classe or the tubed unit after you've experimented. I think that the tubes will fix the brightness while improving imaging, especially depth. Secondly, pick a time when the wife is away and re-arrange the room. Put the speakers at the one end in positions recommended by Cardas. Drag out pillows and comforters for deadening, if necessary. I think that setting your room up on the diagonal may be your big problem as it goes against all the recommendations.
Hope this helps.