The problem is most people want to cast him in dramas, and that's not at all where his talent lies. He really shines when he's being funny. He loosens up and doesn't take himself so seriously, and that makes all the difference. When he's trying to be serious, he clenches up and gets that blank look and worries about his timing and it just doesn't work at all. He needs permission to be loosey-goosey and smile and generally mess around. Then it works. But people nowadays associate him with Neo and Constantine and have forgotten how wonderful he was in his early comedy roles.
(I nearly lost it during his part in "Thumbsucker". Most of the people in the audience didn't get the comedy, but I used to live in Santa Cruz, CA, a old-hippie haven, and I TOTALLY knew who he was playing. I must have met at least 20 of him in that town, including a chiropractor who worked on my back - quite successfully - and spouted exactly the same kind of vague New Age nonsense. Keanu got that guy DOWN and was incredibly funny.)
He was very funny in Thumbsucker. He does funny well, charming well (Something's Gotta Give), cute well (Parenthood), honest effort well (Speed)... and he is athletic. But romances and dramas, yes, he's pretty stiff. It worked in the first Matrix because almost everyone in it was acting the same way. But he has to choose his roles very wisely.
He's very good at being bewildered, I gotta say. I saw The Matrix many times in the theaters, and one time I did an experiment. I tallied up all the questions he asked. I was amazed to find that almost EVERY LINE he had was a question. I think perhaps 4 were not. He didn't really get declarative until the very last moment, when he made that speech into the phone. It was very interesting.
I figured that out about him too, but that's just fine with me.
He also can't do accents, as in Bram Stoker's Dracula". I cringed whenever he tried, but that's also true of Kevin Costner (Robin Hood). I applaud Keanu for making the effort, he knows when he's bad and I can forgive him for that.
The fact that he's good looking made up for his weaknesses in some films I'll admit, though I hated "Johnny Mnemonic", the best line in that is when he says "I can carry nearly eighty gigs of data in my head." the rest was junk.
His new film "John Wick" looks interesting. Let's see how he does in that. Hopefully he won't lose me like he did in "47 Ronin".
I don't think I've ever felt sorrier for an actor than when I heard him do the "I WANT ROOM SERVICE" speech. It reminded me of what Harrison Ford said to George Lucas: "George, you can write this schhit, but you can't SAY it." Just awful, awful, awful writing. I'm amazed Keanu could do as much with it as he did.