Upgrade

Room, speaker positioning and consider subs. The gear looks competent to me.

After those two factors, the tweaky cable/doodads. You could go beyond that with a PC and the latest software too, if you don’t trust your ears.

Maybe before the other stuff, clean power from the outlet if you don’t have decent service to start with.

Forget it and enjoy the music, if the system is in a living space like most listeners.

Go full analog with tubes and a table. That’s my excuse for not having a room. Just obsess on finding the BEST cheap record of amazing music.

Ceiling panels for damping made a HUGE impact in my very "hot" living room.(wood/windows everywhere)

Aesthetics are paramount in my case. YMMV like the rest of the madness.

Edit: I meant to add my system is in a living space, but I'm able to get the speakers in the room(5ft) and away from the sides(3ft) Subs take care of low end duties.

That budget would get you a set of Synergistic Research Element CTS speaker cables that will do exactly what you want - larger sound stage, more liquid and open- and with much greater dynamic punch. You could probably afford to have Michael Spallone upgrade their power supplies for truly jaw dropping performance. The main downside being when you hear just how much difference quality cables can make you will be spending a lot more money on them in the future.  

https://systems.audiogon.com/systems/8367 (These have the Michael Spallone power supply mods) 

Or you could add a full room treatment of Synergistic HFT, both room and speaker kits, not as staggeringly huge as the CTS cables but close. 

But if it really is a deep wide dynamic liquid sound stage you are going for then ditch the ML and get a Raven integrated. You could probably sell the ML and AR for enough to get within $3k of a Raven Reflection MkII integrated, which will be an even more staggering improvement than any of the above ideas. Which is really saying something. https://www.ravenaudio.com/product/reflection-mk2/ 

Those seem like really nice speakers but they bottom out at 40. [from website: 40Hz to 16kHz, ±3dB]

I have some speakers now that go down to 38 hz but the presence of just one REL sub does quite a lot, very noticeable, for the entire spectrum. I got that $1900 sub used for $900 and I am pretty convinced that a second sub is necessary. (Just waiting for a bit to see how some other things develop.)

Perhaps get a sub or two as a tryout and see what happens?