In a small parish, the priest can be a true shepard to all the flock. The priest really knows his flock, family by family, regardless of whether a particular person or family is involved in numerous committees and activities. I think this is critical to the spiritual welfare of the Church.
Likewise I think there are far too few dioceses. I think they should be smaller and more numerous. Thus the bishop can really get to know his flock.
In SC, the Catholic population is small, but the diocese is large geographically (the entire state.) When Bishop Baker was here, he spent his time tirelessly traveling the diocese and was very accessible. (I make no comment on our current Bishop simply because he hasn't been here very long and I don't know as much about his activities-although he has made the effort to visit every parish-but it took over a year. 90+ parishes over such an area is a tough job.)
Just another instance where I think smaller can be better....
Oremus pro invicem!