You never said engineering was ideal, but the conversion to the new system, couldnt be more fair. Make up your mind.
You know it's not a binary condition, right?
It's entirely possible for something to be as fair as it can be without being perfect.
In this case, I suspect it would be almost impossible to find a way to quantify every existing mod and attempt to figure out where it fits into the new hierarchy accurately.
That being the case, taking each mod and making it the top of the previous tier seems pretty reasonable, while also encouraging players to make use of the new system.
I find it bizarre that people who've willingly spend hundreds of hours obtaining mod's are suddenly getting so stroppy at the prospect of having to re-do half a dozen rolls - especially given how easy this will be with the mat-trader. [blah]