world creation in 1.5 and 1.6

How can i create a world similar to normal one, but without those pesky craters in the ground?

I an using worldedit in big style, but even messing around ingame and using sphere and smooth is a timetaking duty.
Isn't it possible to get another world by changing the seeds?

To alert you? You saw the message anyway and this is the place. No need to write in private.

EDIT by Moderator: merged posts, please use the edit button instead of double posting.