I'd really like to not have a graph window open up because I didn't wait long enough to drag a keyframe after selecting it and it's interpreted as a double-click. Why isn't the double-click "feature" optional? Having to hesitate after selecting a keyframe slows me down considerably, and having to close graph windows slows me down even more.

In the Hierarchy Editor it's way too easy to accidentally parent something when I'm just turning things on and off. Why not require a modifier key to parent? Or make parenting objects that way optional?

I don't care nearly as much about new features as I do improving the usability of existing ones. For instance, if I don't wait long enough to start typing a file name after clicking Make Movie, and the name includes a letter used as a keyboard shortcut, it actually cancels the export and applies the keyboard shortcut instead!