There would be no reason to downsize servers like that at this time, as Marty said they are working on them but there is no ETA.
Also, in response to your other post, I guarantee you that Diablo 2 and Diablo 3 are on different hardware servers and this was done intentionally. They are not exchangeable at any time. Just like Starcraft and Starcraft 2 are on completely different servers.
Diablo 3 shares the same hardware as Starcraft 2 - They are both on Battle.net 2.0.