Man, the boosting and grappling stuff is so fun. I don't understand why the campaign decided it was a good idea to not let you use it for most of the game.
As others have said, the campaign resources in all modern cod games go to extravagant one time use set pieces and in the process sacrifice the depth that could be applied to a more solid set of core mechanics. I'd happily ditch all the jet fighters, jet pack, and jetski parts for the opportunity to use gadgets like the mag grips and the grappling hook more than a handful of times.
![Frown :( :(](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Or those little mobile shield drones. The hover jetpack the marines had at the start. Stealth generators. Sniper rifles with more than one shot. Really, any of the stuff that made you a badass super soldier on foot fighting other badass super soldiers.
Honestly the best campaign map was probably the Assault on new Baghdad where you were given a degree of freedom in your movement around an admittedly small area, if only for a little while, lassoing AST from behind and ripping out their pilots. That should have been, like, the campaigns bog standard. We should have been using the hover jet in the first mission to run rooftop to rooftop above the streets of Seoul, or whipping out an assault drone every mission to do some house cleaning. It could even be that the drone can be spotted and shot down, so it's very much a use it and risk losing it item in every mission.
Another common trend in CoD games is that no single enemy is actually a threat to the player character. Halo, you screw up and stand your ground and an Elite can eat your ass on anything above normal. Metro, you can get hose by two or three guys or a couple of mishandled mutants.
CoD. Every mission has a triple digit bodycount. Also, what the heck happened to the Redneck dude? It's like they completely forgot about him in the process of having slightly fewer burly white dudes than the average CoD game.