Sasha and Chris were hired to play the same kind of characters eye-candy that women used to play in the show.
Edit: It occurred to me that Tommy McKay's personality was so different when the character was using cocaine compared to not using cocaine that it was almost like having to play two different characters.
Eddie Peck, he was given a number of clichéd scenes and a cardboard role that he made quite believable and therefore unpopular and hated.
But both of them acted like total wimps the next season.