Touch Flo 3D = HTC-Sense
I too was wondering why my brand new TouchDiamond 2 didn't have touch Flo 3D installed. Through doing a bit of google research I found the following info in wikipedia:
From the HTC Hero and HTC HD2 onwards, TouchFLO 3D has been heavily extended and is now being referred to, along with other usability improvements, as HTC Sense.
HTC Sense is a user interface, based on the TouchFLO 3D user interface, developed by HTC for mobile devices running Android and Windows Mobile. Announced June 24, 2009, the first phone running Android to feature HTC Sense was the HTC Hero, and the first Windows Phone to feature HTC Sense (an updated TouchFLO) was the HTC HD2, announced October 6, 2009.
At the World Mobile Congress 2010, HTC showed their new updated HTC Sense UI to debut on the HTC Desire and HTC Legend, with an upgrade available for the Hero and Magic.
The Windows Mobile version of Sense is the successor to TouchFLO 3D.
Perhaps this addresses the issue you've been having? You can tell if you have HTC-Sense or Touch Flo 3D installed by going into settings, then into "all settings", then into "Today", then select the tab for "items". There you'll find a list of check boxes. If one of the check boxes says Touch Flo 3D then you have that, if not it should say HTC Sense. Checking or unchecking that box will enable or disable that functionality for your phone. Hope this helps! Good luck!!