I think the idea is makes sense but has a risk of going making the "supers" to powerful or not working altogether, the reasons for this are explained in more detail in the thread.
When it comes to tyres, in real-life and in virtual ones, making them our definition of "fair" or "equal" or "fun" is quite difficult but I suppose that won't stop from trying to come up with solutions...
The idea is to reduce hard tyres speed little but not too much that they become useless. Just finished race in China and from my observation hard tyre is at least 0.3 sec or faster then medium. Slowing the hard tyre 0.05 - 0.10 won't make the hard tyre useless for sure just bring it a bit closer to other tyres.