Has anyone actually asked the pools why they don't upgrade? And if they've tested merged mining? Maybe they would have some valuable feedback.
updating software on pools is risky. if the upgrade results in the loss of a block, or worse a bitcoin block, the pool can be substantially out of pocket.
has merge mining with the new client been tested? it should be easy to run a difficulty 1 'ixcoin in a box' network with old and new clients and make sure they accept each others blocks.