Oveur has posted a Dev Blog regarding the reworking of the Mission system in EVE, including adding new mission levels and changing existing missions.
We're also overhauling the top 70 mission encounters in the first Need for Speed agent initiative. It might not sound as much, but if you think that 1 encounter might have itself spawned 5000 times over a day, there's considerable "bang for the bucks" in making them more fun, challenging and perform better on the server and client.
http://myeve.eve-online.com/devblog.asp?a=blog&bid=432