I have to say after working with MC 5 consistently now for at least a month or so, there are a few things that I do like. However, I can not get used to the new Audio Track monitoring options.
I don't like the very tiny and individual Solo and Mute buttons. Not only are they too small to see and click accurately, the previous method of a toggle worked just fine for me. If it was active and you clicked it, it muted. If it was muted and you clicked it, it became active. Brilliant. If you wanted to Solo, you held CMD+clicked it, plus, it was a nice big area to click in because it was the full height of the audio track itself and not split in two as it is now.
Now, there's this confusing mess with the Track Selector Panel and the Power Button thing and two and no way to map any of that stuff to they Keyboard.
I remember hearing that some particular icon changes a few years ago were driven by the fact that as monitors have gotten bigger, the old icons were not as easily seen or recognizable as the newer icons. Yet, we get Solo and Mute icon/buttons that are smaller still. I don't get it.