I'd like to add a feature request for integrated UI plugins. By this I mean the ability to add plugins to the context menus, such as Library Tools.
I have several ideas for plugins, but to be most useful I would like them accessible from the context menus. With this facility, it would be easy to add features like Regular Expression search and replace which I would love to have. I know this could be implemented with a traiditonal plugin, but it loses the power and flexbility of being able to select the tracks you want, rather than having to re-filter for them in a separate screen.
I would think (hope) that this wouldn't be too difficult to implement. At first it could be limited such that you can only add plugins to certain set menus, with Library Tools being my choice. Then when the plugin is selected in the menu, MC creates a dialogue box and displays the plugin UI inside it, and passes to the plugin some object that defines the selected items which the plugin can then iterate through to do whatever its task is.
I think adding this sort of power will further increase plugin development because there are a lot of useful tasks that could be added which would greatly benefit from being able to run like internal MC tools do.