Wil's character on TNG was my least favorite, even as a kid watching TNG growing up, but I don't believe that is his fault. Clearly the writers did not know what to do with him, and its likely his performance is a result of whatever direction he was given. In the later seasons, particularly in his final episode regardless of the ridiculous "traveler" storyline, his acting is much better, likely as a result of older and more easily relatable. I guess this is all to say he was good at acting, you only need to watch "Stand By Me" to see that. If he had been worse at it its likely his mother would not have been so successful at forcing him to continue to do it.