I will most definitely be using this patched client with my p2pool node.
But I also agree that we should not be enforcing any absolutely transaction exclusion policy on an address basis. HD wallets are not implemented yet, I'm not sure that the standard has even been totally finalised. De-prioritisation sets the right balance until the landscape of listing develops further, we must in the meantime educate users across the whole community of users about the issues surrounding all of this.
Edit: Question to Luke Jr.
I assume this cannot affect the prioritisation of the Coinbase transaction that constitutes p2pool miner's reward payments? Can you clarify this?