Amps have sonic character. If you were to buy another Mark Levinson of equal or greater level it would probably have the same character, but with much better performance. For much of the last 40 years I had Pass amps and found a significant (worthy of spending money) every ten years. I would think ML would be the same.
If you are changing brands then the character is going to change, maybe a little maybe a lot. My tastes have changed dramatically over the decades as I have been exposed to much more live acoustic music and recognized the emotional connection that my system lacked. This caused me to change my approach to amplification. Mark Levinson is a very respected brand, but I have always found it lacking in emotional connection. This certainly does not mean you will.
I think you are in a great position. Not in a hurry to make a change… basically pretty happy. Time to browse. Take your time and listen to different alternatives. You have the luxury of not doing anything unless something sounds great. Go listen to Boulder, Pass, Audio Research, and a couple more.
If you are not near dealers make a couple “audio” trips to the city… spend the night, make appointments at high end shops to listen. Take your wife… dinner, go hear some live music. Make it fun for both of you.