Strange case of Dr Jekyll and Mr Hyde

I am still thinking about what impressions this book left me with. It is one of those classics that everyone thinks they know (or at least, I did) and it was a bit different than what I expected.
First, the language was flowery and circular, and it had me rereading paragraphs more than once, distracted by the unusual constructions. Well, not unusual - simply, the book was published in 1886, and it shows.
Second, the reasoning for Dr. Jekyll to try and become Mr. Hyde seems so... flaky! Basically, it was never an extrenous pursuit of science, as I first thought, or pure instinct taking over, as I assumed it would be the case. Of course, the moral impact is huge and Dr. Jekyll becomes more and more swamped by all consequences of what he did, but how it became reality in the first place is a bit strange.
Third, I missed an ending more elaborate than that. There was a letter from Dr. Jekyll, and we know he (or Mr. Hyde?) was deceased. (I'm hardly giving you a spoiler here, come on). But why exactly is he dead? There's nothing from Mr. Hyde, either. I don't know, it seemed it could be more exploited, after so much argument on morale.
All in all, I can hardly argue the main idea, that is absolutely great and original to the time. And it was interesting to read it, as an adult, with those images of cartoons and so on in the back of my mind and so much darkness in the story itself. But still, I expected more.