Post your build. Something sounds like it's wrong. Perhaps you have something that is fast attack yet somehow being prioritized higher than rend.
However it seriously sounds like that, despite what you say above, you haven't actually done a clean install. Close DemonBuddy, delete "CompiledAssemblies" folder in your DemonBuddy folder, and restart DB. This isn't as good as a clean install, but is the next best thing. Do you have other plugins in your plugins folder that are disabled, but still there? Are you selecting "GilesPlugin" as the combat-routine choice when you hit "Start"? Have you tried the change I suggested in this post;
[url]http://www.thebuddyforum.com/demonbuddy-forum/plugins/67705-plugin-giles-trinity-59.html#post707964[/url]
To see if that improves things at all?
Have you tried altering the Rend code manually to increase usage (personally I find mine spamming Rend almost too much, but there we go

). Have you changed your skills while DB is already running (this is never good)? Have you tried starting DemonBuddy while on the character select screen and letting it log in and run the routine for you, rather than entering a game first before clicking start?
You're the only barbarian that has posted saying something so dramatic as to say your deaths per hour have actually dramatically INCREASED with 1.4.4 Trinity, so I can only assume that you have done something wrong, or you have an unusual skill build that most barbs don't have and one of the skills you rely on got changed for the worse in 1.4.4.