In competitive TF2, he is considered the second most important target, only the medic is more important to kill on the opposing team.
If that doesn't convince you, then I'm sorry, there's no hope for you in this subject and you shouldn't post in this topic.

My main issue with Demoman is that he can use the sticky launcher very aggressively and potentially decimate the opposing team, which it should be able to, but not on offense as easily as it does.
My idea for balance on the Sticky Launcher is this: Make the stickies armed after they've been "stuck" for half a second or maybe a full second, this would encourage demomen to play more defensively, as they should.
What do you guys think?