Further annoyance with the alt search box thingie: you can clear it, and when you reboot it comes back again. So reconfigure it to something you'll never use like Rshift, l-alt, r-alt, super.

You can fix a lot of these problems with compiz-settings. For example - you can get a better alt+tab switcher and disable the default one.

> How do I switch to another instance of the same app?

Yup, you need compiz settings. Some of the plugins are very deliberate hacks around the shortfalls of unity. You could start here: http://askubuntu.com/questions/43875/how-do-i-adjust-the-alt...

If you don't find what you need, have a look through package management to see if there are any other compiz packages - these might give you more plugins.