I'm not sure I agree with that. I used to use panes-style browsing in iTunes until my library got too big for it to be useful.
Now admittedly, I haven't spent much time with the panes view inside MC18, but it doesn't seem very different.
With Library views, I can completely customize how things are displayed depending on the genre of music (classical is listed completely differently from "regular" music for example) or any other number of variables.
I can look at the same group of items, but have them sorted differently - for films, I have a library view that shows everything, then sub-libraries for "new" and "seen" films.
Beneath that, I have various views set up that will sort them alphabetically, by date imported, by my rating, by critic ratings (for new films) and a number of other things.
With the panes view, you only have one view that you can narrow down to a selection - that's only useful when you know what you're looking for, and hopeless for browsing.
I wouldn't mind having the column on the left auto-hide though, as it does in cover view. (but with the controls visible at the top)
If you're just wanting to hide it though, double-clicking on the resize bar seems to do that. (I want to do that, but have it appear when I mouse over the left side of the screen)