Acceptable arguments are:
o Switches can handle more throughput
That's difficult to quantify in theory *or* practice.
o Switched networks are easier for humans (or at least, humans without
huge brians && many internal registers) to design/debug/maintain.
More levels of indirection does not mean it's easier for humans necessarily.
In fact, there are many more nobs to miss, and more places for error to
be introduced into your engineering model.
o Switches are requied because without going to a smaller decision space
(re: how much work per unit the switch/router has to do to decide where
to forward the data unit off to), existing routed technology can't
support moving IP packets at the desired speed while having to evaluate
the 40-60k routes we'll have soon.
But stuff that's in development sure can..
Dave