CD Player upgrade. Is it worth it when using Digital Coax to an AV system?

Hi Folks,

Just so you know my setup...

Rotel RSP-1098

Rotel RMB-1075

Rotel RCD-1055

Pioneer BDP-51FD

B&W DM604S3

B&W DM602.5S3

B&W DM600LCR

B&W ASW300

LG TV blah blah HTPC beside it etc etc

Just looking for everyones opinion on this. I regularly listen to CDs, so I do get good use out of the Rotel RCD player. But heres my problem. I was under the impression that its the CD players DAC that is primarily responsible for the sound quality that can be obtained from a CD player. I.e. There was a difference in sound quality between my old NAD C521BEE (20bit burr brown) and my RCD1055 (24bit Burr Brown) due to better DAC etc.

However, when I use a Digital Coaxial cable to connect my CD player and Blu ray player to the RSP1098, it bypasses the CD players individual DACs and then uses the DACs of the 1098 (which as the old flagship rotel receiver, id like to think are better than both). So Would I be right in assuming that there is no point whatsoever upgrading the CD player to the new RCD1520? In theory all thats happening is that a laser is reading the data from a CD and sending it to the RSP. Lets be honest here, a laser is just a laser is it not...!? Or am I being Naive? I do however, assume that things like power supplies are indentical between 10 and 15 series rotel equipment!

Anyones thoughts is much appreciated!

Iain