This is a perfect and enjoyable campaign, and the only problem(except the crashing issue) I can think of it is in the Finale, the Tank spawn point is too unpredictable for the first-try and the environment there is too narrow and full of obstacles, which can causes deadly friendly-fire on the Expert difficulty. Though players can retreat to the bottom of the parking lot, the field there is still not big enough for rotating and one can be desperately cornered by Tank.

Surprisingly, in a Singleplayer walkthrough, this is not a very serious dilemma, because the AI teammates won't cause damage to each others and they're all actually shooting Tank. But when playing with other players, one Autoshotgun user can easily kill other three Survivors, then get killed by a Smoker if they're not careful.

The Parish's Finale has a similar design, and Valve did put many obstacles near the Tank battle point too. But obstacles on The Bridge are mostly small cars, and not only that Survivors can jump on them to keep a distance, Tank can also make use of these vehicles to attack(though AI Tank is not that smart to do it.) What's more, the Bridge is more wide for Survivors to create a safe firing range and run around to dodge Tank's punches and rocks.

Next is about my own opinion; I honestly think that fighting one Tank in a small and cramped place is not enough exciting. One of my favourite campaign, Farewell Chenming, has an epic Finale including 4 Tanks coming from 4 directions and enough supplies on a big piazza. There's no word to express how stimulated I was when I first played that map 2 years ago, but until now it's still a big shot in my heart.
So, as my own advice for Freezing Point's Finale, I think the Tank position can be put more behind, at when Survivors get on the surface and hasn't seen the monster truck, and also spawns TWO Tanks instead of one. I think this is reasonable because on the surface the place is more open, so not only the problem I mentioned above will be gone, but also provides enough space for a fierce Double-Tank battle.

And that's all. Still, Freezing Point DC is one of the best maps I've ever played, but if you can take my advice or give a think about it, I'll be sincerely appreciate! :)