Which sound qualities, of the ones listed above, are you enjoying now? If there were no or low cost ways to improve your system, do you have the time and patience, to pursue them? In no particular order, you may consider : making small changes to speaker placement and your listening position, examining cable organization, elevating speaker cables off the floor, changing the position of devices under your speakers, changing the amount of furniture (and its placement in your room). And countless other issues (see Jim Smith’s “Get Better Sound”)
It may help to identify what you are not happy with, today. It wouldn’t be too much fun (to me) to make major changes in equipment and always wonder if the very best sound was wrung out of from today’s setup…