I felt very similarly regarding screen real estate usage efficiency when migrating from 8.5.3 to X1 - I struggled with my 2 20" monitors, which had suited me just fine for years. I would agree with someone's point above that I don't like Sonar's default template at all - and have found by creating a few default screensets into a default template that suits my personal taste, I've gotten past the real estate concerns.
I prefer mouse clicks to shortcuts, as my keyboard retracts into my desk and don't want to pull it out everytime to use a keystroke shortcut - so would like customizable quick icons at the top of the screen like most software products in the world have, but oh well, such is life - I've gotten past that and now click file - save.
Admittedly, I'm not leveraging some features within the skylight UI (multidock and quick access to the browser), but by setting up a couple screensets, I can easily switch to views across all available screen real estate to display just the console view, just the track view or a mix of both depending on what I'm doing. I'd agree the ProChannel is a BIG reason to upgrade. It's allowed me to stop worrying about most 3rd party plugs, which pays dividends in stability, price, integration, screen real estate, etc.
Give it time - you may feel similarly, but I would seriously recommend creating a default template you feel comfortable with and include some different screensets within that default template (screensets are project-specific, so by saving them to your default template, you'll have them for all projects).
Hope that helps.
Russ