Man, I am so out of the Doctor Who loop that I didn't even hear about the new casting! I had a bit of a crush on Ten, so I never minded the Doctor being a man, but I am excited by this. I do agree that the Doctor is more a title than anything.
I haven't really developed much of an opinion on gender/race bending, apart from that it can result in some fun reimaginings. More powerful representation should probably come from original characters instead of being derivatives of the "norm".
Personally, Twelve is my favorite, but I guess it boils down to preference. The lengths those internet trolls go through is staggering. Personal attacks on actors is just too much. If anything, they could just not watch if they hate the casting so much.
Agreed with the original characters. Mainstream media is so used to just leaning on derivatives that they don't want to take a risk on unproven characters because they fear it'll flop. Thanks for stopping by and reading, my friend! Safe journey :D