The Gen 4 uses exactly the same OE MS as the Gen 3 as far as i am aware. And I have to say the brakes on the Gen 4 are leagues ahead of the Gen 3. On my Gen 3 brake fade was something fairly common on track in OE spec but a lot better once the pads and brake fluid was upgraded. My Gen 4 though, not an issue so far. I swapped the pads for Brembo SC and the fluid is changed to Motul RBF 660.
Personally before changing the MS I would change the pads and a brake fluid to something that has a higher boiling point than stock. Brake fluid should be changed fairly regularly in my opinion if you are using the bike a lot on track. It is hygroscopic so absorbs water, water has boiling point of 100?c, (your brakes will be getting hotter than that) as such that water will turn from a liquid to gas and then give you a nice squidgy feeling. (both in the lever and in the bottom when the bike doesn't stop)
You said there is only around 1mm of material left on the pads that isn't really enough material left to dissipate the heat properly. On the road this is fine as you probably do not get the pads working that hard but on track it is a different matter.