Alas, this show is entirely geared to saving people rather than booting them out. You could always beg for everyone to vote for the better dancers, but then this brings up what I think has caused the problem with voting this year. There are too many good dancers. This series had more pre-trained dancers than ever, lots of whom became very good very quickly as soon as they got past their nerves and first week stumbles. If you have one vote to cast, and you're a viewer who votes purely for dancing, that's a lot of people to choose from. If you vote purely on entertainment, there are fewer contestants to choose between. If, probably like most viewers, you vote as a mix of dance and entertainment and personality, then your vote is likely to go to the best dancers with the most appealing personalities. In all of these categories people like Gabby and Penny suffer. They're not quite the best dancers (although very good indeed) so maybe miss out on a lot of the votes cast by those who vote purely on dancing, they're not hugely entertaining from a personality point of view and so miss out there too - and amongst all the better dancers, they're personalities are not hugely appealing. Gabby in particular was very difficult to warm to and I completely was not surprised when she ended up in the bottom two. Penny again, whilst very sweet isn't very interesting.
If they had a lesser number of pretrained contestants, the 'entertainment' vote would be more heavily split - and I think you'd find on the most part the better dancers stayed in.
Personally I find Kate a joy to watch - though I've never voted for her. But I find myself willing her on each week and I'd much rather sit and laugh at Kate and Anton's self-deprecating humour and have-a-go attitude, than wince at Gabby's steely determination and sour face when she doesn't get the highest score of the competition.