Key adaptations provide an interesting perspective on the “lead character”. There is, of course, the main main person, and then the loads of other characters whose arcs go in a round. So, oddly, during each arc, the protagonist becomes the focus of the arc, “she” becomes situational, and our “point of reference” character becomes a kind of third party instigator. Due to the primacy of the reference character, the one whose introduction was first, we might have the tendency to view him (Yukito, Yuuichi, Okazaki) as the protagonist even when it’s not “his arc”. The fact is that during other girls’ arcs situations are already established beyond the control of the male reference character, so he must then act accordingly within the boundaries already set up by the temporal protagonist.
The audience is treated to this reference character because if we simply went through various arcs without a human anchor of sorts, we’d either end up with something as unorthodox or seemingly unstable as Kaiba or a bunch of nonsequential, unrelated, confusing bits. The male reference character is supposed to act as a way for the audience to insert themselves into and latch onto those situations already established, but, as other people have noted, it seems to fail in Clannad because the arc scenarios are too unrelated and hastily ended to be memorable or appear “natural”, not according to realistic things like gang violence or social ostracism, but to the depth of human emotion. I think Kanon had the same issue (maybe a regular person would have had a mental breakdown with the amount of stuff Yuuichi experienced in the period of a few winter months).
Essentially, and this seems like a pitfall of adapting visual novels into anime, since Okazaki must be in each arc regardless of his function – and often is his function so contrived that is detracts from who ought to be the protagonist – both his and the situational protagonist’s character are downplayed because we’re slightly confused as to whose eyes we ought to view the situation through. Both reference character and situational protagonist are temporally developed as lead, and so their conflicting positions work not in harmony but to the detriment of both characters. The anime backfires on itself precisely by, as otou-san succinctly put it, “doing too much, yet not quite doing enough.” Previously, I had written that (at the time I hadn’t thought about it like this) this poly-faceted viewing strategy proved valuable, which I guess isn’t a lie, though I won’t fib and say I don’t like Clannad or Key adaptations. I do, and I can picture BigN saying that “what matters is that we can write intelligently about anime regardless of its receptions.”