Yup. After unlocking the sith base on Taris, I didn't use the little r2-d2 clone until I had to unlock Uthur's door... and then never again.
Carth was also never used after Taris except on his quests, same with mission, zaalabar, hk-47, and canderous.
If I had gone dark side, I suppose Canderous and hk would have had some use, but because I went light side, just juhani and jolee... why waste time with somebody who shoots lasers when instead I could have somebody use forcewhirlwind, heal me, and smack people down with lightsabers?
Because I had a soldier, I used mission all the way through on Taris because of her skills (that is until I got Bastilla).
About halfway through the game (and this is if you go soldier/guardian), leveling up skills (Besides that of your main character) becomes pretty redundant, because the chances of you using them are slim... if you go for a scoundral/consular combo, then other characters skills... ARE useless.