One thing I have noticed is that every plugin rolls their own database access and configuration structures. If Bukkit provided an API for basic CRUD DB access and a "Bukkit Registry" style configuration API it would not only simplify plugin development but also combine a lot of code for servers running multiple plugins. It could also provide a common in game command set for manipulating plugin settings which would simplify server administration. Also since this could be used for many plugins effort to optimize that code would greatly improve server performance and resource usage. It seems a fairly small amount of code here could make a huge difference for all Minecraft servers. If this API was built in a modular fashion it would also help to be able to simply modify Bukkit to support multiple database platforms. That way one change could migrate all their database access from mySQL to Oracle or MS SQL Server. This would really help the bigger servers.