I think Doghouse Riley is right - they do a different job. I'm not entirely sure that being Bruce's sidekick is such a great gig - at any moment, I keep expecting him to ask her to do a twirl... I'm no fan of Tess (her utter inability to pronounce Ola's name correctly speaks volumes about her intelligence), but she does a very good job of keeping things moving along nicely in the results show, and when she stood in for Bruce the other week as the main presenter. She can, at least, read the autocue...
Claudia is a kooky delight and excels at the off the cuff stuff, so is ideal for the role of interviewing the couples after the dances. Zoe is like an half-trained Labrador puppy - all enthusiastic and energetic, but not entirely under control, which I'd argue is just about the best balance for her role on ITT.
All in all, I think the three women do a great job and would be even better if Bruce weren't around - then their respective roles would work perfectly.
Oh, and I'm sorry if the OP feels the board is vitriolic - perhaps it would appear less so if forum members didn't feel the need to start threads with quite such provocative titles as if they were facts rather than a matter of taste and opinion.