I know Barricade got whupped on by Ironhide. At least got a wheel torn off. I can see how they'd let Bonecrusher survive, a robot's anatomy doesn't have to be like ours. The human body can parish with less than 1% damage, but a bot, that could be a totally different deal.
I was bummed they killed Jazz. "Nobody kills a Pontiac in my town! Just be glad it wasn't my town."