For me not doing it its definatly more the talking side. I am happy to do gameplay without talking but an actual lets play I think people would find boring. Gettig some new gear soon and will probably actually start doing lets plays.
I think capturing the right sort of audience is a good thing I mean there are already lots of lets plays for popular games. I am thiking about doing some of my favourite childhood games like digimon world Absolutely love that game.
I will say that I personally watch a lot of the LPs here that aren't pokemon ones. I liked the sim city one that was done (made me re-get the game) but I never really post as I have no idea what to comment.