Something good would be this :
1 The Magneto Sapper
Has triple of an electro sapper's health

Takes twice as much time as an electro sapper to destroy a building

Anyone getting near the sappered building will see their speed halved
2 The Tranquilizer gun (watched same youtube clip as you

)
50% less damage

Slows down enemies on hit

Drops disguise only after critical hits
3 The Dragonfly knife
Stabs/weapon switchings are performed twice slower

Can be used while cloaked

Cloak lasts 250% longer

Adds 10% cloak on each hit
The youtube clip looks pretty fake, everything we know is that Valve will release "Meet the Medic" with the update.
Note* The Tranquilizer gun has been seen in Trailer 1
Reply and tell me if this idea is good or bad