Whenever you have coloured wools, stained clay blocks and stained glasses or panes, the colour may doesnt seem appealing to you and you cant change the coloured wool or stained clay blocks into another colour. So basically, what I wish is that we can re-colour it by simply putting a dye in the middle of the crafting table and surround it with the blocks that you wish to colour it. It is simple and easy to re-colour using the crafting table.
The Meaning of Life, the Universe, and Everything.
It shouldn't require a cauldron...
While cauldrons DO need a use, I think people are just scrounging to find a purpose at this point.
The TS's original idea makes a lot more sense to typical minecraft mechanics. I was very surprised as well when I came to the realization that you can't redye wool or clay.
I don't know if mojang didn't incorporate the feature on purpose because they believed it to be too easy, or they just forgot, or who knows. It would probably be more difficult to dye some items since some dyes aren't so easy to get (i.e. ink sacs)
The only thing undye-able colored wool/hardened clay accomplishes is wearing down the player's tools...