I concur, however the fact of the matter is the physical limitation of the device. The newer routers, (unfortunately/fortunately based on your current purchasing position) are going to probably have this MAC table cap raised.
It's sad too because the 655 is truly one of D-links finer moments. Like the 604 in it's day. If MAC filtering is your thing, and you have that many devices, then this router just isn't for you. I'm sorry, but thats the long and the short of it.
However there are options, messy and time consuming, but they're there.
Radius, or other authentication type servers can be implemented to achieve the same end.
We are listening, and striving to make the product better.
