Your expectations of Frankenstein are largely due to Hollywood's interpretation. Frankentstein is referred to as the work which gave birth to Science Fiction. Not bad for a story that was more-or-less fleshed out over a weekend.

I think you're pretty spot on and fair to the book though. If you're reading Frankenstein and you're expecting a thrilling horror novel then you may be disappointed. If you're interested in the ethical questions raised by the creature being created, abandoned, and left to deal with it's strife over having no companion... then I think it's a pretty great read.