What I try to remind the naysayers that they are probably presenting a decent point for consideration but this isn't something you just share an opinion on.
A contribution has to be valuable and for it to be valuable it has to be a real effort to do. Roll up your sleeves and slap on the elbow grease: it's gonna be some hard yakka but oh so worth it, even if only 50% of what's on the table so far comes to fruition!