I actually think West has reached his potential - not every player has the ability to be a superstar. He was passed over by NZ franchises, he spent some time as a wider training member for the Chiefs and brought in as a injury replacement for the Blues. He has never been a player to drive a game - more of a complimentary piece which is why his best Super Rugby has come when he's had someone at 12 to take the pressure off (e.g. Nonu or Francis, not that im comparing Nonu and Francis as players)
I think ideally West would be a really good Super Rugby bench 10.
One player i'd like to see at 10 for Blues is Otere Black - but it doesnt look like happening. Be interesting how Perofeta goes if he gets some time later in the season.