BRF+ is just a way to configure a standard-delivered workflow template.
You can always build your own to replace it. However, there is no reason why you should re-invent the wheel. My advise is to always try to understand the standard solution rather than trying to fight it. Whatever time you invest now in understanding how it works will be worth it down the road.
Take a look at this document and hopefully it will help you with the rule-based workflow: http://scn.sap.com/docs/DOC-51559.
Try it and if you have any specific challenges, post questions here.