Clearly the fee system is suboptimal if one can reduce fees by workarounds that increase system overhead.
I learned long ago that it is much better to create a sub-optimal system that is simple and robust than to try to create a perfectly optimal system.
Pretty darn good, with the right incentives in place to drive the long-term desired behavior, is good enough for me right now. I think "we" have been pretty good at responding fairly quickly to problems as they appear. I'm keeping a close eye on the free-transaction backlog, but I think tcatm's recent changes to http://bitcoincharts.com/bitcoin/ , showing transaction priority, and the recent change to the bitcoin client, so the default fee rules are the same for miners, relaying across the network, and the client, are working nicely.