I'm not disappointed that we have a young Doctor. But it would be nice to see an older Doctor - late 50s early 60s. I don't see why someone that age couldn't cope with the production schedule. The reason I'm thinking this is because Patrick Stewart, for an example of an older, physically fit actor, does long stints in Shakespeare leads and he can pull it off. I don't think age is necessarily a bar from that point of view. However, I do suspect that a younger actor will appeal to the "target" audience more. And in any case, to young 'uns watching the show what they see as older isn't necessarily older to some of us. I'm thinking of Steven Pacey in Blakes 7. When I saw Blakes 7, Steven Pacey was older than me buy a goodly few years and therefore seemed "older", now I realise he was barely in his 20s and just a kid! 
