On the contrary, a newer router will probably come with a faster, more powerful processor and more memory. It will likely have better quality of service management software and with Apple, one would hope better cooling capacity. (They HAVE been getting better).
It might not be a difference at all for 1 person and a couple of devices, but a whole family's household of devices and dealing with a neighborhood with a lot of competing wifi networks? Yea, more powerful controllers help!
I wonder if newer ones have better abilities at dealing with noisy signals...
Oh yea, and there's ALWAYS ROOM FOR IMPROVEMENT in the storage controller department; accessing a hard drive connected to an AirEx isn't all that fast, even over wired connections, and a better CPU allows for a faster (or ooo.. dedicated) controller!
anyway! Just adding my two cents on that topic