Microsoft is really daft at promoting Windows 8.1. All they have to do is spend some big advertising bucks to point out the following 2 things (which are deal-breakers):
1) Windows 8.1 has a Start button.
Right-click the Start button to get a menu showing Programs and Features, Power Options, Event Viewer, System, Device Manager, Network Connections, Disk Management, Computer Management, Windows PowerShell, Task Manager, Control Panel, File Explorer, Search, Run, and Shutdown (Sleep, Shutdown, Restart).
Left-click the Start button to get to your commonly-used programs. The tile screen is a Start Menu, and is configurable to look more like (sort of) the type of Start Menu you've understood in the past. You can configure it inside of Control Panel/Taskbar and Navigation/Navigation.
2) Windows 8.1 can easily switch between recent apps by clicking in the upper-left corner of your screen.
This is provided that you enable the option in Control Panel/Taskbar and Navigation/Navigation which says "When I click the upper-left corner, switch between my recent apps."
When Microsoft released the Windows 8.1 Preview to the public they should have put a little video on the desktop pointing these things out. If they had done that people would have warmed to it super-quick. Instead, Microsoft is going with the plan of not making it obvious that the major features that people think aren't there are already there. They are burying the information about these things inside of lots of other information so that these major points don't stand out.
One a side-note, Microsoft released Windows 8.1 Enterprise Preview today. It is the same Windows build number 9431 as the Windows 8.1 Pro Preview. It has everything that Windows 8.1 Pro Preview has, plus some additional features for developers and those who manage an Enterprise environment.