Honestly they should not bitch no matter what, I know they love to drag out the excuse. "Oh but time lords get younger the further they go into regenerations" wrong! The Original Master was on his 13th regeneration I believe, and he was played by an older actor.
You're right, it doesn't exactly work like that...I think it's stupid how that's their excuse...like how they want the Doctor be a lady for once...it doesn't work like that, how would marriages work out, then? .-.
I could understand skin colour...that's incredible likely, but gender seems to ridiculous to me, if you're a timelord born a certain gender you should only be able to regenerate as that same gender...I could imagine how weird things were on Gallifrey if it works like that...imagine almost dying while you're in the middle of giving birth, then regeneratating into a guy .-.