I'm looking forward to series 5 so much, (it's not long now) Matt Smith is going to be great, and if you saw "Friday Night with Jonathan Ross" then you'll already know that, but from the moment I saw MS on DW Confidential I immediately saw how similar he look to David Tennant, (he's not an exact spitting image of him, obviously) but the bone structure in the face is similar, and when I saw a Promotional Poster for the 11th Doctor, where he was standing next to the Tenth you could definetly see a similarity in their appearance.You can't really deny that Doctor's 8 to 11 look the same, they've all got the same Hair Colour, the same Bony structure in the face, the same thin, lanky, gangly frame, pretty much the same height and they wear the same dull black and brown colours, the only real difference between them is their persona's. Gone are the days of the Classic Series where The Doctor's physical appearance would completely 100% change, (for example Pertwee into Baker or even better Colin into Sylvester) each Doctor had their own distinctive look. Back in the day, after The Doctor regenerated, the main reason he used to change his clothes was because they didn't fit him properly anymore, but nowadays The Doctor could keep his predescessors clothes on because they still fit perfectly (in the Christmas Invasion the 9th Doctor's outfit fitted the 10th Doctor like a glove and it was the same in the closing moments of The End of Time, why would the 11th doctor need to change when his old clothes still fit).
When The Doctor regenerates next I would love to see a complete makeover, when I heard that Martin Clunes could be the 11th Doctor it made me smile because I knew that he would be completely different in peformance and appearance to DT in every way. But at the moment I'm perfectly happy with Matt Smith, and at least his peformance will be different as well as other things such as The Tardis and the appearance of the Daleks etc.