: I'm talking about the fact that after the first game you can't man the gun
: without being driven to your doom or being taken away from the fight and
: parked against a rock.

I think that in each game after H1, I've given the Marines one chance at taking the wheel with me aboard. And I'm pretty sure that each time, I got killed within seconds because of absolutely dumb driving - so that's the last time I bother trying it. H4 was no different there. It was just the same old story.

: I'm talking about gunners that don't shoot at
: visible targets, that fixate on shooting corpses when a Wraith or Ghost is
: bearing down on you.

I noticed them seemingly shooting at bodies a few times in H4, causing me to turn in readiness for trouble - which wasn't there. So that was annoying. Looked like an AI failing, rather than being intended as gratuitous shooting.

: I'm talking about how it's often a good idea to exit
: your Hog on the Coastal Highway mission in ODST and take shelter behind it
: as soon as you are under fire from a single Ghost because ~1 second of
: sustained fire will kill you.

Enemy vehicle fire has been way too lethal since at least H3. It was one of my complaints then.

: If 343 was prepared to do more work then I would like to use the buttons that
: are unused when driving or gunning to enable fast position switches and to
: let me toggle driving from the gunner position.

Your suggestions sound good. I'd expect the hog to at least slow during a changeover though, as a token bit of realism. I'm thinking that swapping places at full speed probably wouldn't be too healthy in real life.

: They could also tone down 'taunt enemy corpse'

I'd say they need to remove it entirely, as it merely seems like an AI failing. Should be easy enough (and because of that, I'm finding it hard to imagine why the situation with that is presently so bad).