I don't really hate any of them but Michiru is my least favorite. She kind of just feels like pairing fodder. Mamoru at least had two seasons to develop as a character before S turned him into pairing fodder, and Artemis never feels like one.
I documented it for the first two seasons. The first seasons should be pretty obvious, so here's the list I did for R:
Episodes
Usagi: 47, 48, 49, 50, 51, 52, 53, 55, 56, 57, 58, 59, 60, 61, 64, 66, 68, 69, 72, 74, 75, 76, 77, 79*, 82, 84, 86, 87, 88
Chibiusa: 60, 64, 66, 67, 68, 73, 74, 75, 76, 81, 82, 85, 86, 88
Ami: 55, 56, 58, 62, 71, 72, 76, 80, 82, 84, 86, 88
Rei: 54, 56, 63, 70, 72, 76, 82, 84, 86, 88
Makoto: 49, 55, 56, 58, 65, 72, 76, 82, 84, 86, 88
Minako: 52, 56, 65, 72, 76, 78, 79*, 82, 84, 86, 88
Mamoru: 50, 53, 56, 58, 59, 61, 64, 66, 69, 76, 77, 82, 83, 84, 86, 88
Tally:
Usagi: 28.5
Chibiusa: 14
Ami: 12
Rei: 10
Makoto: 11
Minako: 10.5
Mamoru: 16
The asterisk was actually a Luna and Artemis episode, but since it gave Minako and Usagi more screentime than the rest, I counted it.