I am enjoying my analog system, but what can I do to improve?

My music room is essentially a small box (10 x 10 ft) and I have fair amount of treatment in it: sound absorbers and diffusers.

@noromance, I only need one phono input. In terms of budget, I would say <7k. But I would like to be slightly under the proverbial point of diminishing returns.

New cartridge will thrill you, not because there’s anything wrong with the 17DX but because of our nature as humans.

This my usual suggestion for people in your situation. 

My music room is essentially a small box (10 x 10 ft) 

That room is a killer but I've been there myself and you can get good results, pull the speakers out a little more if you are near the wall and put your seat all the way back.  

Knock down one wall of your listening space.

I would venture to say you have hit the limit of what you can achieve in that room. Changing out components won't get you any closer to the level of realism you want. I would look at appropriating another room in your house.

Oz