Again, nice effort, but not quite in the same category. Williams was traded for #8 and #39 which Collingwood turned into James Clement and Brodie Holland and in turn played 5 seasons averaging 18 disposals and was handy. Kerr would demand a lot more and he is rated way higher than Williams ever was.
I had a look back to see what trades were done with a quality proven midfielder and a decent number of draft picks or players and I realised that besides Judd it hasn't happened obviously cos' clubs just aren't willing to pay the price for them but as I said earlier they are willing to do it for KPP's and even some of them turned out to be flops like Adelaide's trade for Carey. So it would be a very brave move to try anything.