I liked the cast. I thought they had more potential chemistry between them than was allowed in the writing. Malcolm and Trip's friendship could have been developed more as it provided a lot of comic relief. I didn't like that Reed became a tight arse in season 2 (not wanting to have dinner with the captain, not drinking etc). I liked Reed as the bit of a playboy brit that I thought the Pilot introduced him as.
Trip's character was lost to T'pol and most other characters got less interesting as the show became Trip/T'pol/Archer much like Voyager was Janeway/Seven/Doctor.
I know it's in the contracts that these character have more episodes but it can be tiring when the focus is on 3 main characters. I'd rather Reed, Trip and Archer as a Kirk, Bones, Spock type trio.