People misinterpret the "no headshots" buff. It means no DEATH from headshots. So if you get hit in the head you have 1 hp left and can't take further damage from headshots. The Scout's 25 Hp buff is nice, however, he's losing his primary mode of attack to basically become a support class and only has a 4 shot pistol and a melee weapon to do damage.
EDIT: It IS a scattergun replacement, but it has the ammo of a pistol and it's max damage is 70 from what I understand (I can't get into tf2wiki for some reason). I've seen the scattergun do 107 or maybe even 110 at close ranges. With the full set the scout trades off being badass at killing to being helpful. Personally, I'm just a fan of vanilla tf2, and the new items do not scare me or make me worry about game balance. Except the wrangler, that thing is still a bit broken.