The demo's new weapon will be a button that kills everyone, everywhere.
can you say "nuke"?
I mean, he is a demolitions guy. It would be possible.
some speculation on my part:
soldier:
rocket launcher replacement:
homing missiles
tracks and homes into enemies, explodes on contact or after 5 seconds
slower than normal rocket launcher
less ammo
shotgun replacement:
hand thrown grenades
its possible than the soldier will actually use the grenades already attached to his body. They are present in every "meet the.." and in the game it self, it's only a matter of time until he uses them.
Similar to demo's grenades, except no power shooting. Can only adjust angle of throw for distance.
shovel replacement:
sword
faster swing
capable of disabling limbs, ex. a hit to the leg will slow down or stop enemy, a hit to arms/torso disables use of weapon, etc
capable of "knighting" allies (touching ally on shoulders with sword), which gives "knighted" ally a speed and weapon boost
disabled limbs can be healed normally with health packs or medics
I can't really say much about the demo. I haven't played much as him.
but how about this:
demo:
replacement for all weapons (this one weapon replaces all 3 weapons)
Nuke
kills all, including allies, within 10000 yard radius
causes all to be blind for next 5 deaths regardless of server/map change
causes permanent random mutations in random surviving entities on field
causes all hats being worn by dead to be deleted
can only carry one at a time
slows down carrier, slower than heavy
causes server to crash due to "frame buffer overflow"
causes people still running vista to crash with blue screen of death
causes random name changes
causes random hat/item spawning