Downey and Guy Ritchie weren't over-selling the slashy aspects of the film. If anything they weren't talking about it enough, because short of an actual on-screen snog, there was hardly anything but the not-terribly subtle sub-text. There's "old married couple" vibe, there's innuendo, and there's massive lack of chemistry in either of the on-screen het pairings. I know that House is based on Holmes to some extent, but in this movie, Holmes was acting like House, right down to attempts to sabotage Watson from having a love life aside from him.
I was not really impressed with RDJr's British accent. In fact, it was really hard to understand him a lot of the time, because he didn't seem to feel it was necessary to enunciate at all. I think he got it into his head that he was doing "method Holmes" and decided to channel Brando and James Dean. He sounded considerably more convincing speaking French.
I don't mind a lot of the stuff, although I think the fighting scene was pretty gratuitous fanservice to get some half-naked RDJr.
The referencese to Watson's gambling seemed to be completely random, since it was never developed. There's one scene where he looks like he might be tempted, but if there was ever followed up on in the script, it didn't make the final cut.
It's not that I disliked the whole movie. It was a fun romp, but it was a bit mind-numbing and not as good as it could have been.
Now the promo for Iron Man II? That looked really good.