> Mouse and key events are essential complexity.
I disagree, but probably not with what you mean here. Mouse and Key events are the first thing I want to abstract away, and are an example of the pitfalls of events. The majority of internet connected devices have neither a mouse nor keyboard. I don't want to care about key events or mouse movements, but rather user intent. "submit" and "change" describe user intent; I don't give a shit about clicks and keydowns, or blitting glyphs into an input box or moving the cursor on command-a. What does keydown mean when a Chinese person is swiping chinese characters?
I think of events as chemotherapy. It is one hell of a powerful tool, but should be avoided for most problems. If every problem looks like cancer, then your worldview is missing simpler and less powerful but better tools.