Personally I don't mind the start menu being fullscreen. What really bugs me is how I have 2 incompatible desktops. I have my desktop which I have had since Windows 95. I then have some weird application space and jumping between the two is really unintuitive.
My bigger gripe is the name. Windows 10... It's PHP all over again.
Windows 7. Windows 8. Windows 9? No.. far to logical. Lets call it 10. Perhaps because it is 10 years since 95? I don't know. Still feels wrong.
Like PHP
PHP 3 PHP 4 PHP 5 PHP 7...............