Ah, but when I was younger I could tolerate younger Doctors. :)

Seriously, I thought at the time that Davison, Tennant and McGann were all too young for the role. Eccleston had so many other problems for me that his age was entirely overshadowed. The others, apart from Hartnell, mostly managed by sheer presence to make age irrelevant to their portrayal, which is the ideal...but in general, you can only be ageless if you've aged a bit. Otherwise you're just young. Tennant is still young. It doesn't matter how many times his Doctor says "I'm so old now" and such like, he is callow and unfinished and easily cowed and just not right.

The pictures I've seen so far of David Morrissey look young in the same way, though that may just be the character he's playing, and it's unfair to judge a performer on a still picture. But I believe there was a conscious decision to make the Doctor more accessible to yoof, and I think it was a wrong decision, and casting someone--okay, not necessarily someone in his or her fifties, but someone capable of playing him as the timeless alien that he is, would go some way to redress that mistake.

They won't, though.