WE will improve with starts, but very low WE won't improve very much. Same for attributes. Anything below 10 will never be high potential now, and most people believe that the attributes are on something that resembles a curve where improvement is slow at the ends (when the rating is very low or very high) and more rapid in the middle. If the potential is high-high it will improve faster, but even then if the player has very low WE and a low starting value he will almost certainly never come close to reaching that potential.