Technically not a bug but should be. Peaceful means no monsters trying to attack you/kill you. However even in peaceful places one can die of hunger and of casualty (Ex: drowning or fall off a cliff) I propose Peaceful Mode should be upgraded to normal Mode (Still named Peaceful)  just without the monsters but you will need food, shelter from lightning, and stay away from fires.  it is impossible to befriend a dog on peaceful because there aren't bones at hand (skeletons) unless you find a pyramid with bones. So i also propose that animals when killed not only drop meat (wool/leather/feathers) but also at least 1 bone so we can use for Dogs. Everyone is excited for the Nether update but this would make us pacifists happy to just build, farm and be with friends. I hope you will implement this soon.