Wide(ish) bars and short stems are great. A short stem doesn't feel twitchy to me but then that's all i've ever ridden with on my own bike.
Tried various demo bikes and mates bikes and any stem 60mm or longer feels sluggish and horrible on downhills, not a fan at all.
As for bars I like something that is slightly wider than my shoulders that gives good stability going down, but not so wide as to get stuck in narrow sections.
As for being wrong about something, i'm willing to admit that a granny ring does have certain advantages and isn't only for pansies.