Well, first I'll answer your question about the quote you mentioned: Hartnell's Doctor, though not in appearance, was much younger than Smith's Doctor. The First Doctor was around 200 or so, whereas the Eleventh Doctor is over 1000 years old.
I don't think Matt Smith has ruined Doctor Who. He's one of my favorite Doctors, actually. I know a lot of people, especially fans of the new show specifically, had a hard time letting go of Tennant's Doctor (you perhaps being one of them seeing he's so high on your list), and may not have been seeing Smith's Doctor in the fairest light.
The Eleventh Doctor seems so much more alien than Tennant's, or even Eccleston's Doctors, and has personality quirks that seem to hark back to classic Doctors. He's fun but he can still teach you so much.
Aside from my personal opinion, it was Matt Smith that has brought Doctor Who to America as more than the cult show that it was in the 80's. So, I don't believe he has ruined Doctor Who. If anything has, it's the writing he's given (though I don't agree with that), as some people believe it just isn't as good as it used to be.