Check it out:

The pyro gets a melee that crits on wet players

The heavy gets a minigun that shoots fire off the side (built in spy-checking)

And a new....wait for it....

Sapper (that's right) - This new sapper decontructions:
Advantages: Sentries, dispensers, teleporters go down levels to destruction now,
making repairing a lot harder
Disadvantages: Does not outright destroy a level 3 sentry :)

Enjoy