I got to agree, having a Doctor's predecessor show up in his premiere to "legitimize" the new guy is a bit of a disservice to the new Doctor. All the passing the torch stuff should be handled in the regeneration scene (and has been). In a Doctor's premiere he should make a bold declaration of "I'm the Doctor now. Deal with it."
Sometimes they have made that statement too loudly, though.
"The Twin Dilemma" is basically an exercise in the new guy saying 'That chap in the Cricket whites? What a loser!', as per:
DOCTOR: Change, my dear. And it seems not a moment too soon!!!
DOCTOR: I'm not 'people', Peri. I happen to be *me*!
DOCTOR: It's the most extraordinary improvement.
DOCTOR: My last incarnation. I was never happy with that one. It had a sort of... 'feckless charm', which simply wasn't me!
PERI: You were almost young. I really liked you. And you were sweet and...
DOCTOR: Sweet? Effete! Sweet? Sweet! Sweet? Huh. THAT says it all!
DOCTOR: You may not believe this, but I have fully stabilised.
PERI: Then I suggest you take a crash course in manners.
DOCTOR: You seem to forget, Peri, I'm not only from another culture but another planet. I am, in your terms, an "alien". I am therefore bound to different values and customs.
PERI: Your former self was polite enough.
DOCTOR: Oh, but at such a cost! I was on the verge of becoming neurotic.
DOCTOR: I am the Doctor, whether you like it or not.
Sometimes I think a little... affirmation that this is indeed the same guy can be good. The opposite situation, taken to extremes as above, leads to a bad taste in the mouth.
