I'm disappointed as well. I thought it would be an actual mission, but instead it's just a wave-based encounter in a single room. That's not the worst thing, but the mechanics for the "APC" are not that creative. You just plant a bomb and run away. And the "APC" doesn't even move. It's basically a turret.
As for the waves themselves, the difficulty comes from nade spam. The APC fires a rocket with a large aoe that forces you to move. It's also a 1-shot kill. That in itself isn't bad, but it kind of feels like they couldn't figure out any creative ways to make it difficult, so they just threw in a huge aoe attack. Otherwise handling the waves wouldn't be too bad.
You also don't get any loot unless you beat the whole thing, so if you aren't quite geared up for it you have to go back and grind the challenging missions and dailies, which are no longer difficult or enjoyable. They should have had a mini-boss every five waves that had a potential to drop loot, or something.