Call me a persistent pain in the neck, but I don't buy it.
The change in flavour profile of the latest Taliskers doesn't seem to equate to "quality of casks".
We all know that - using an Islay malt like Caol Ila, example - a peaty whisky will remain a peaty whisky......whether you put it in a fresh cask, an old cask, a good cask, a bad cask, a sherry cask or a bourbon cask. THe peat was infused into the malt and sometimes also present in the water. Filling that peaty whisky into whatever type of wood will not remove the peat. Maybe over 15-20 years or greater, the peat might take more of a back seat, but in a 10yo like Talisker, the peat should hold its ground.
Now I grant you that the type and quality of cask will affect things such as sweetness, dryness, astringency, vanillin extraction, and the whisky's ability to take in the environment. But at its root, it all starts with the base new make spirit.
The peat, spice and pepper that has disappeared from Talisker are features that - IMHO - come chiefly from the new make spirit. They would be due to things like the amount of peat used in the malt, the length of time the stills are run for, the temperature that the stills are run at (affects things like reflux, etc), the length of the middle cut, and so on and so forth.
I am more than happy to accept that the Talisker Distillery made some changes to these aspects of their production 10 or so years ago. But to blame it on the wood seems a little far fetched, IMHO.