The difference you're noting is as follows:
-Some builds do nothing BUT be a chain tripper. This is unoriginal.
-Other builds use UMD as their main combat tactic, but do like a dozen other creative things aside.
Now, if there was a build that just optimized UMD out the wazoo and didn't DO anything else, ok, I'd mark that bitch down in a heart beat, since we've all seen it before. Similarly, when a chain tripper who does lots of other things shows up, I don't mark it down.