To be honest, I think only Mark has ever claimed that it was straight forward.
I have said it's straight forward, it's not difficult to understand and the calculations are done for you by the provided spreadsheet. The system doesn't take any special skills it just requires the ability to follow directions and an attention to detail. Once the number is created for a stock boat it's as easy to use as DPN. Let's not forget... DPN is supposed to use a measurement formula for new boats too.
Given a choice I would NEVER sail under DPN <insert all DPN flaws here>. The OA just needs to have the backbone to commit to the system and be ready to push back on its detractors.