Mini was the one who said last week that HV repeat their contestants a lot. She should definately not be one to make that statement as she has always used her contestant Prachi in every episode.
Harshal Vithal definately repeat Kartik a lot, but the reason for that is probably that they only have one girl on their team (and she has sprained her ankle so cant dance, plus she is a little overweight so cannot be in all kinds of lifts). So since Kartik is so small in size, he is easy to use for lifts etc and that is probably the reason they use him so much...
Also, I feel as though WY have less contestants on their team... but aside from Rahul and Vishal, Shashank and Santosh have also given solo's already and Rahul and Vishal have done a duet too. And aside from Shashank, all the rest of their contestants have been given excellent comments by judges. So I think WY are using their players wisely, but not to the point of ignoring them or not allowing them exposure. Kartik's use is probably simply because of his size...