Sorry for the delay… no this is not possible, but I could add a site setting for it.
I also usually prefer order:latest as a default for stuff I am searching for. Cause I like to use search to recall a topic I recently looked at.
Another option could be to give significantly more weight to recent stuff while leaving it as a “smart search” But… to be honest … maybe order:latest is simply a better default… @codinghorror?