Randy picked up on something I said on Industry Misinterpretations and ran with it - the ability for the New Prerequisite Engine to differentiate between prerequisites that must be there, should be there and can be there.

Now that we have this facility, I was disappointed with how behind the entire prerequisites UI was... so I've updated it and published to public store as NewPrerequisiteEngine 34. I'll post up some screenshots of it. It's nothing fancy, in fact, it's a major simplification over the old UI. But it lets you force prerequisites, mark prerequisites that are there as optional - and of course, compute.