The best way to stop having to wonder how much better things can get is to actually go out and listen to various live music performances in various venues and various systems that attempt to nail it. Even if the cost is out of reach, then you still know where the bullseye is and there are many ways to do very well targeting it for lower cost. Knowledge, focus, and experience is your friend. Try to go to an audio show if ever one you might attend near where you live. Capital Audiofest was this past weekend in DC and no better place to hear many good sounding setups all in one place and learn what makes each one tick
Nothing wrong with any of your stuff on paper.
What is "broken" with the sound of your system that you want to "fix"? How bad? How much of teh problem is the room itself? Best to understand your room acoustics before making any major costly changes. Might inexpensive (example adding a rug on floor in front of speakers) or even free tweaks like playing with speaker placement help? I would work to feel comfortable that you have done what you can to optimize what you have before changing a thing if not already the case.