I think you're absolutely right about DW having an element of SH in it at a very fundamental level. It's not something which has really been pointed out before, or if it has, made much of, but of course, given Moffat's involvement in both, the similarities are finally being discussed extensively and we're all slapping our foreheads and going "duh!"

I suppose what I was trying to say - and it's still hard to find the right words - is that in Sherlock, Moff can concentrate on the things he clearly likes to concentrate on - plot, humour, dialogue - and not bother too much about characterisation and helping the audience to forge an emotional connection with the characters, because thst's not really what SH is about. And of course, for many DW fans, it's not what they think DW should be about either. But here, Moffat was able to give us enough to make us care about and begin to identify with Watson, but becuase he didn't need to go any further, it didn't matter or leave people like me feeling that something was missing. Does that make any sense whatsoever?!

I think that BC has a look of Matt Smith about him - small, pale eyes, prominent cheekbones and a general look of "otherworldliness" (Matt was up for the role, apparently).

I thought of the Westminster Bridge scene as well!

I noticed that "Shut up - I'm thinking!" got a repeat airing ;-)