You have a very nice classic receiver and I wouldn't upgrade just because somebody says so. Of course you can do better, but give it a try before spending money needlessly.
One point about relative levels between phono and line level inputs: Most line level devices(like a cd player) put out on the order of 1-2 volts, whereas a phono cartridge outputs a few millivolts, and regardless how much gain you have you will ALMOST always have to turn your volume control up when phono is selected to match the other sources. And some records are cut at a much lower level than others which requires even more gain.
BTW, I have some vintage (70s) marantz separates that still serve me well in a bedroom system
Jim
One point about relative levels between phono and line level inputs: Most line level devices(like a cd player) put out on the order of 1-2 volts, whereas a phono cartridge outputs a few millivolts, and regardless how much gain you have you will ALMOST always have to turn your volume control up when phono is selected to match the other sources. And some records are cut at a much lower level than others which requires even more gain.
BTW, I have some vintage (70s) marantz separates that still serve me well in a bedroom system
Jim