Brad Abrams looks like he's found out about Zymurgy's First Law of Systems Dynamics with his post on changing from Hashtables to Dictionaries in Whidbey:

Once you open a can of worms, the only way to re-can them is to use a bigger can.

My thoughts on the matter are pretty much in line with IanG's, but I especially agree with him when he notes the lack of compiler support for composition/delegation, which often provides a cleaner solution than inheritance. See my "Spoonful of sugar..." (of the syntactic variety) post from couple of months back for my take on this somewhat more fundamental issue.