The clue-combining mechanic is a great idea and I felt very clever when I worked something out. I agree that the vast number of clues made this unwieldy, though, and I too only got one motive figured out before I had to stop playing. (My suggestion: Remove clues, or mark them inactive, when they've been successfully combined and there's nothing more to do with them.) But I did appreciate that there are too many clues to just brute force them--you do genuinely have to use reasoning instead of just guessing!
The amount of dialogue felt way excessive to me, especially the opening. I spent a lot of time waiting to click the continue button. I also wasn't going for the art--in particular, the character portraits, which didn't seem to match the character descriptions or how they appeared on the map.
Still though, great core mechanic. I'd just like to see the game trimmed and focused so we can really sink our teeth into that clue-matching.