More health=/=stronger.
The Demo weapons do more damage in my experience.
Soldiers have perfect straight shots.
Demomen have grenades the size of large oranges that bounce around like rabbits and require PERFECT AIM to even hit a target, and Sticky bombs dont even work half the time.
Its distance vs. short range.
If you have a gun and someone has a knife, and both are 20 feet away from eachother, who would win in a fight?