I like the idea of Tegan taking over for the shouty bits.
Lowdarzz, sorry I get what you mean now. The under-utilisation of one of the three companions is a bit of a reccuring theme in the 5th Doctor's stint (when there are three companions of course).
It's weird but I hated Adric for a long time, but recently I've reappraised him. He's annoying, but I don't hate him, and at times he's quite interesting because he can be very amoral. In some respects he's a sort of proto-Turlough. Although where Turlough sides with bad guys out of fear, Adric almost seems to do it out of logic.