Eh, Reeve was 100 percent great, including his Clark. Mind you, I personally prefer a less exaggerated take, more “Clark is the real guy” a la Dean Cain. But Reeve did what he did and did it superbly, and it worked brilliantly in the context of those films.
This is not really the actor's take--the two Clarks were portrayals of how Clark Kent was being written in the comics during those time periods. In the 70s, Clark's whole shtick was that he was klumsy--he tripped or fell or dropped something in practically every issue (or often enough that's how I remember it). By the time Lois and Clark came around the character was very much influenced by Byrne's take on the character, which did away with Clark's clumsy, weak-stomach act.