So you'd get rid of the graphical stuff? Why?
I'd like it if we could turn them into "everlasting potions" by combining large amounts of them in a cauldron (the number needed going down with the ql of the potions added).
What it would turn you into should be fixed after the combine, so you could have an "Everlasting Barrel Potion"
The everlasting variety could have something like a 72 hour cool-down between uses.
This would add more value to yellow potions, and I think we'd see people actually transform a lot more often.
The main problem I can foresee is that yellow potions are used as incentives for staying premium... and that incentive would partially go away if someone had an everlasting one.