I am about to make a router table out of a piece of corian. It will be an
awful lot easier to simply mount the router base to the corian than to buy a
plate and cut and route out the corian to accomdate the base. Besides, with
no base I don't have to worry about the base not being flush.

When I asked about corian a few weeks ago someone said it wasn't rigid
enough to hold a router. But wouldn't epoxying some oak supports across the
bottom, just outside of the base, make it pretty darn rigid? (I might even
epoxy the base to the table and eliminate all the screws. That ought to
enhance rigidity.)

So why are plates important?