I hadn't considered the possibility that Craig's unconventional (for Bond) looks may have actually contributed to his casting, but it's an interesting idea.
As you say, Brosnan failed to make much of an impact because he was sort of a walking "greatest hits" package of what went before, as opposed to anything radical or fresh. I believe if you'd had a police sketch artist draw up a picture of "James Bond" in 1994 based on the combined descriptions of thousands of daydreaming fans, you'd end up with something that looked, walked and talked like Brosnan.
And yet, that's also what keeps him from standing out, in the end: turns out you can only get so far building your 007 from a kit. So maybe it was intentional that they went entirely, 100% in the opposite direction with Craig, picking a guy who looked the absolute least like anyone's conception of how James Bond "should" look. Anyway, it got my attention: I had sworn off Bond after DAD and if Brosnan had stayed on for another, it would've been the first I'd missed in the theater since 1979.. not because I hated Brosnan, but because it would have signaled a continuation of the status quo, which had become (for me) unwatchable.
When Brosnan was cast, I think the reaction was something along the lines of "well, duh..." He was the safe, obvious choice, whereas when Craig was cast, the reaction was more, "Say what?!? Okay, you're going to have to sell me on this one." It raised the interest level. People showed up because he was so different, just to see how it could possibly work, and in more than a few cases, to watch him fail so they could say "I told you so." It was a very gutsy, ingenious move.
I don't want to give the impression I hate Brosnan, because I don't. But out of all the Bond films, I consider his the most expendable; the ones you could skip entirely without really missing anything. I actually loved TND on first viewing and went back less than a week later to watch it again. Partly this is because I got in to a free preview the first time and wanted to make sure Eon got at least a little of my money. In 89 I won tickets to LTK and saw it for free: I never went back for another viewing and then Bond was "dead" for 6 years. I felt responsible.