It depends. If the system is very good, I’d definitely pursue optimizing it. It’s a great way to make subtle personalized changes to suit your tastes and room. I chose that path 30 years ago with what I thought was a really nice sounding system, and have refined it since....isolation, wires, bi-amping, power supply upgrades, mods, tube rolling, etc. Nirvana on a budget!
Starting from scratch can cost a lot of money, and is a shot in the dark whether or not it’ll get you any closer to where you want to go.....it’s so subjective and room dependent.