Movies growing dark is one of my biggest issues as well This also translates into TV programming in which seasons work like sequels. Make it bigger. Make it darker. More explosions. More angst! Part of my exuberance for the upcoming Guardians of the Galaxy is how jazzy and fun it looks. Like I'm sure the story will have brooding angst at some point, but a thread of silliness is a welcome.
My problem with Cumberbatch has little to do with his looks. I find him attractive and unattractive as his looks/roles change. But I don't find him the second coming in terms of acting and in fact his work for years now has come across as forced, unnatural. I feel frustrated when I try to point this out because he's always praised for his talent. To me, his Sherlock is a menagerie of ticks; I think he lost all attachment to a real character back in season 2.
I also don't find him to be a particularly nice guy as I think he comes across as very full of himself in interviews and has said some annoying things in the past. He's not overly atrocious or anything, and can back peddle pretty well. I will never forget an NPR interview with Moffatt he gave back when doing press for Sherlock Season 1. There were obvious comparisons made to the RDJ movie. He effectively said that while RDJ was a fun character, he was not playing Sherlock Holmes. At the time I secretly agreed. Now I laugh at the irony, because while his character is a fun Bond-like sociopathic detective, he's *not* Sherlock Holmes.