I'm sure in one week he didn't install an entirely new defense, but if you even just look at where players were positioned that next game it was obvious things had changed. I'm assuming those formations (if you call them that) were in the playbook, but not being utilized by Smith? It was a significant change in position on the field and responsibility.
The fact that Smith couldn't figure out where to put people on the field in order for them to be effective says a lot. I still think his entire defense was predicated on having an Antoine Winfield type safety that could cover up everyone else's sins, and there ain't that many Antoine Winfield type safeties out there.