Hi and welcome to AiKiDo,
I went the other way, taking up Tai Chi after several years of AiKiDo. I'd say that what you describe is fairly standard in many schools of AiKiDo. Some of them emphasize pedagogical technique explicitly, but most of the places I've been the instructors just sort of demonstrates or 'teaches' whatever is on their mind that day or that week.
Perhaps one of the reasons this works is that, fundamentally, there really is not all that much material to be learned. I haven't 'studied' as much as a lot of people around here seem to have, so I'm not sure that I really know how to break down AiKiDo into a bunch of component elements and examine them individually, but in general there aren't a lot of them. Just a couple of days ago, I was visiting Irene Wellington's dojo in Saint Louis and she said: "tenkan and irime; that's basically all the footwork we have in AiKiDo." The number of attacks is, of course, very limited and from each attack you can do more or less any of the 'techniques.' On top of that, each place I've visited has a few basic techniques that seem to show up in every other class, so at least some of the variations start to look very familiar very quickly.
The real question is why it's taught this way. Of course, I have no real clue. It just always is. I like it because it seems to help me learn through my body more than through my mind. It helps me understand the idea that there are many different connections between the different techniques, and to see how they connect up in the teachers mind by watching the flow of the ideas through the class.
Of course, maybe I'm just being knee-jerk conservative about how I learned it ...