I don't use schemas for a few reasons. First, why would you ever put multiple application data in the same database? Brr. Besides, that's what four part names are for if you ever need them. 😀

Second, there are tables that should logically span multiple schemas, so which schema should they go into? If you're using schemas for security reasons (which is really the purpose of security groups so why be redundant?) then you'd have to grant access to an entire second schema to get to the one table needed by members of another schema--which defeats the purpose of schema security!

Third, there's no reason you can't use SPs exclusively with the dbo schema, again, that's what security groups are for.

I'm a BIG proponent of vanilla design--use the bare minimum number of features you can get away with, especially avoiding redundant features. The more features you involve, the more things that can go wrong.

Sure, if you MUST HAVE some feature, by all means use it. But if it's redundant then don't.

KISS for the win!