I've pondered about this from time to time.
An entire profession to design different and unique essences and cores.
The profession can create Cores that all ready are filled and are as one piece (nothing can be replaced) as you would a normal crafted piece of gear.
Also, can create essences that would require mats from other broken down essences.
Quality is entirely based on the matts and which essence you break down. if you want something comparable to a 100 ISS then that's what you must break down something comparable.
The difference and bonuses of these crafted essence should be very clear.
This profession has limitless possibilities and would drastically reduce farming.
Perhaps make recipes extremely rare for the good stuff etc etc.
I've got plenty of ideas but my mind is elsewhere.