Do one thing better than anyone else in the world may seem overwhelming. There's always going to be someone better than you at some one thing, so do one thing better than most, maybe? I think it's really hard to be the best at something, so personally, I'd rather focus on doing something different, or to just have a slightly different spin to a concept. I haven't read the whole book of the Blue Ocean Strategy [
http://en.wikipedia.org/wiki/Blue_Ocean_Strategy], but I find the author's concept interesting.
For a product with lots of features versus specific, I think it just depends on the consumer. For some, a camera included in their cellphone is enough, but a device that is specifically a (dslr) camera can be 1000x times better.