I'm not 100% sure these are the right application, but Army of Two and The 40th Day.
Neither one has you face the big bad in a firefight (without the alternate ending DLC, which I think was free for Ao2, but still). The first at least has you fight Clyde, or whatever that dude's name was, but still. I sort of expected a fight beyond that (which they gae you in the alternate ending).
Then there's the second one, where the final fight is just another hall of bad guys, essentially. And while I only sort of expected a fight in the last game (Dalton was not a merc), I totally expected Jonah to be more than a cutscene with a shitty ethical choice.
The third has a boss fight you'd expect from a game like that, but made up for it by being kind of stupid. But I digress.