That's what we've done, and it's been a huge help. There are a few areas where it's a little complex (things like build servers; does each environment get its own? That makes it so we have to duplicate effort on the build server rather than knowing it really -is- the same build. But if it's shared across environments, it has -accounts- across all environments. So tradeoffs). But in general shooting for isolated environments has definitely been of benefit.