AV Receiver Upgraded


Hello:
I have a Denon AVR-4603  Surround Sound Receiver for the past 13 years,  and it is still working fine, no issue at all. But the question is: 
Why should I upgrade to a new AV receiver such as Denon 4700 or Marantz SR6015, what am I getting? Why would you upgrade?
And Yes I do have the Sony 77" OLED TV.

Mando..
almandog
Unless there’s a newer feature on the 4700 you need or want (4K, streaming, etc.), don’t bother and just continue enjoying your 4603. 
Looks to be an awesome unit, highly respected sound quality, the cons were only about it's complexity, which I have to assume you have mastered.

I would only think about the speakers, fully satisfied? or some improvement possible?

After 13 years, I would disconnect everything, clean all jacks, connectors, back together, there is the potential to recapture ____?