This bothers me as well.
I interpret "Mi sciis tro" to be "I knew too much" and I interpret "Mi sciis multe" to be "I knew a lot". These two statements mean different things, after all you can know a lot about a topic without knowing an excessive amount (too much) for the situation at hand and vice versa.
Mi esperas ke estas leciono nur pri la diferenco "sci" kaj "koni", cxar mi ankoraux ne komprenas.
(trying to say: "I hope there's a lesson that's only about the difference between "sci" and "koni," because I still don't understand." corrections are welcome, as that's the most difficult sentence I've attempted so far, by far)
Yes, but here's the thing (or one of them): When one "knows too much," it's generally not referring to "I knew too many facts" in the sense of knowing information, it's "I knew too many secrets." Maybe that's colloquial/idiomatic? "Mi sciias la faktojn de fiziko." Or...okay, Esperanto treats an absence of something not as a quantity. Multe da librojn but manko de librojn. Wouldn't "mi scias tro multe" be equivalent to "I know (what) too much (is)," i.e., knowing how much is enough, knowing how much is too much? Or is that what "mi konas tro multe" would be? If I know (konas) the book is: I've read that book, I can quote from it vs I know (scias) the book is: I've heard of the Quran/Koran but I've never actually read it...Oh, now I'm just more confused. Some of the things that aren't natural to English come to me fairly easily, such as per vs kun vs kontraux; konas vs sciias, not so much.