Modern Commentary
With newspaper comics, the Sunday comics' storylines are traditionally independent from the weekday comics. This is for a few reasons. Firstly, some papers only carry the Sunday comics (or only carry the weekday comics). Secondly, since Sunday comics were in color, they needed to be completed a few weeks in advance of the dailies, so the color separation could be done in time.
We have neither of those excuses here, but since these comics were a donation goal, we might not know whether to include Sunday comics or not until after the story had been written. So standalone Sunday comics were our best option; writing larger comics and hoping we'd get to use them - or rewriting things at the last minute - wasn't our style.
But also, Kimberly won't stay melancholy forever. I like how she bounces back from the last comic. - Terrence