As mentioned by another answer, other than defragmenting the disc and deleting and then doing a repair of the game files, deleting the local cache, local.dat, does provide a performance improvement.
Local.dat is located in %appdata%/Guild Wars 2/. It contains many local configuration settings, such as keybinds, graphics settings, set nicknames on your friends list, and the size and location of UI elements, but it also contains cached lists of assets for frequently visited areas. In areas that have undergone changes, GW2 may use the cached asset list, load the assets, and then load a whole new set when it goes to see what else it needs.
If you delete local.dat, GW2 will rebuild it based on the most recent version.