Look out, rookie forum-poster here - I'm certainly no expert, but my experience suggests the the latch tightness is related to how high up are the big plastic screws which support the corners of the hood.
To explain - I refer to plastic screws which stick up on the frame just behind the radiator, to the left and right sides of it, big 3/4 in. diameter hex-heads on 'em. Didn't notice them myself for a long time - I'd just let the hood fall, and it would rattle a bit, lotta buffeting at highway speed, and I noticed it seemed to sit low above the headlights. No prob with the hood release being tight.
So one day, I figure out, "Hey, the corners of the hood must sit on these things," so I screw them out a bit so the hood level would match the fenders better. And whaddya know, it worked, but I had to slam the hood down harder to get it to catch.
::Takes a breath:: The punchline is, immediately afterward, the hood release was a total ***** to pull. On the third time I tried to open the hood, that wheel beneath the handle that the cable goes around snapped off. Near impossible to pull that cable with my bare hands. I figure, hood sits too high on those pegs, and the latch closes so tight it makes the release stick. I learned my lesson - I backed those plastic screws down a half-turn or so, and the hood release cable became at least bearable to pull on.
Now, being I was dumb enough to buy a used car from a dealership without checking it out first, who knows if my problem is the same as everyone's. But it might explain some of the cases of tight latches.