There were "old" actors who played the Doctor before, and it's only natural for his regenerations to get different appearances in age. The people who are complaining sound more like fangirls than actual fans who enjoy the show for the show and not the actors. (though DW has had some heavy hitters) 

Martha had a decent ending but I didn't like her joining UNIT just like I didn't like Rose sort of becoming a military sort of person, I understand their to need to keep learning about space but it just hardened their personalities and made them much less human to me. At least the show could admit it ruined the companions lives since the Doctor had so much guilt in Let's Kill Hitler. 

Anywho I must focus on my post...or homework. Not sure which. >____> I made a pie and did laundry so I've already accomplished something. Eheh.