Odo? Oh, the rubber man from that Star Trek? That's not a very nice thing to say. He think he's more of a cross between Tommy Cooper and Herman Munster myself. Ha!
Funny that you think Rory Kinnear is significantly older than Matt Smith! He's only 35. Seems like stripling to me. 40-55 is probably my preferred age range. Although that said, Matt Smith, turned out to be perfect in the part, so what do I know? I never thought of him as a foetus either (you have some very strange notions, I have to say) - in fact, I rarely thought of him as being 30, but could easily believe that he was 1100. So that worked.
You're right about one thing though. The new Doctor has probably been chosen - they just haven't announced him/her yet. Might be Kinnear, we'll find out soonish, I expect. I think my choice at the moment would be for someone like Tom Hollander. Or Miranda Hart.