When extending an event with your cursor by dragging the event out, you have to spend a lot of time lining up the cursor to the perfect spot where the icon changes allowing you to extend or shorten the event rather than move the entire thing. This process is tedious and time consuming, especially when you are making a series of manual adjustments.

I propose adding a hotkey that you could hold down that automatically puts you into this "extension" mode. For example, I hold down the option key and then my cursor changes to that extension mode and I can click and drag freely across all the events.