On further inspection, it is not the identical paradigm but seems constructed on the same principle.
Your're right,
valo declines almost identically to
aika, but not exactly. I recognize it as a
auto-type word (ends in o, u, ö, or y), and the difference is that the partitive plural is formed simply by adding
-ja. The
aika-type words ('officially' a
kirja-type word per
Finnish for Foreigners) require changing the final
a to
o before adding
-ja to the genitive stem. Actually,
aika is a little strange -
k disappears as it should according to consonant gradation but the
i morphs to a
j:
ajan instead of
aian.
There's real value in distilling a large paradigm into a smaller paradigm; the question is always which subset will be most helpful and still be sufficient.
Absolutely agree. I just looked at KOTUS and there are like, 50+ different paradigms!

I learned probably fewer than two dozen types in
Finnish for Foreigners, but they seem to cover the bases just as completely as KOTUS. It appears that the word types that I learned, while possibly a bit more complex, are sufficient. KOTUS has two or three models where I have just one.
I have anything but a computer-like mind, but I am somewhat analytical and have an unsettling urge to know
why things are done in a particular way. At this point, I've learned to recognize most of the word types along with their associated patterns to the point where violations like
kirjia and
paitia actually sound wrong. And when I accidentally invent a "new" Finnish word when trying to express myself because my vocabulary is still limited, at least I'll get the endings correct!
BTW, my primer on Finnish grammar was
Finnish for Foreigners, which I found to be pretty good at explaining the why's and how's of the language. Boring and dated lesson topics, though - the book really could use an update.