Other than the heavy mittens (which are awesome) and the engie wrench the stats for the weapons are all terrible ideas. I would say I expected better but since the Tomislav and its original stats I can't honestly believe that Valve understands and cares about balance. Models are nice (perhaps not fitting with the original theme but that ship sailed long ago), and I really liked the comics for this update. I would be playing to check out the new map and take advantage of double drops but steams not working at the moment for me (not even offline mode, so not even any New Vegas for me ) .
The models fit with their package. And they're still in line, with the psedo 50-60s era that TF2 takes place in. These are just the retro future guns of the era.
And, playing with the new weapons, and being attacked by them. They aren't really OP. Wrench isn't an automatic get out of jail free card.
Pyro feels stronger with his new primary, but its range is shorter then the flamethrower (it feels like), and the "MMmm" bar, giving health and crits, is just reenforcing the ambush and dive in gameplay that's popular with the pyro. Pyros will often jump onto a point with tons of enemies, to set them all ablaze (fucking fun), and to hold off the point capture. This, just makes them more affective on their own, which the pyro generally is.
The handgun (for the pyro), isn't OP. Being able to extinguish with it, is nice, since you cant do it with the primary anymore. It even rewards you for doing so, by giving you mini crits for it. Which is nice, considering, that air blasting isn't rewarded in the game proper. (I personally like Servers that give server points for extinguishing team mates.)
I havent gotten to play with the axe very much yet. I got either borrow one again, or craft it. (And crafting this new weapons are /fucking/ expensive. I went through getting a class token, slot token and a scrap... and I got a fucking back burner.)