RVM/VMM ships with some pretty useful built-in components and applications. RVM/VMM's Atomic Generator is probably one of the most powerful ones, yet it's pretty basic. It can definitely help you generate a flow of random items but it was not intended for generation of sequences. A sequence (scenario) is a set of items that have some sort of correlation between them. For example - consider a set of 6 transactions where the transaction 4 depends on the previous transactions say transaction 2. Atomic generator can not generate this kind of sequence, RVM/VMM addresses the need for smart scenarios with the "RVM/VMM Scenario Generator"
Since we can not anticipate the future enhancement in the verification environment it is better that we provide the flexibility in the verification environment for generating scenarios. Selecting scenario generator will be the right step.
The deployment of scenario generator in the verification environment is slightly complex that deploying an atomic generator, but we can have the complete controllability on the micro transactions in a sequence using scenario generators. Deploying a scenario generator in the verification environment will help you in the longer run, also you can randomize between scenarios.