I am developing a plugin to do source code indexing and autocompletion for Objective-J.
I really need the autocomplete menu to be able to be wider. I hope this screenshot demonstrates the need in an obvious way.
My plugin completes methods, complete with parameter hints, so they can be pretty wide. It works great for short methods, but for longer methods, the completion hint becomes truncated to the point of uselessness. See the completions near the bottom of the menu for some examples.
Allowing custom completion schemes is a really winning feature of ST2. I have more suggestions to come, but the most bang for the buck would come from just allowing the menu to be wider.