the gameplay and platforming feel largely the same, but there are a lot of improvements in the gameplay than previous titles. they added more layers to gameplay, level desgin, physics, AI, new melee system, Stealth and new features like the rope that just all add to the gameplay experience.
- stealth. the stealth is greatly improved in UC4 over UC3, and due to the larger and more complicated levels, transition between stealth and action is pretty seamless. its pretty much the best way to complete an encounter. stealth for as long as possible, then when you are caught, fight then try to break the line of sight and ambush them when the time is right.
- Larger levels with more veriticality and space. the level desgin is top notch, and approaching each encounter will never be the same, due to how big the levels are and how enemies react in it. they created huge playgournds for the player to fight in, that include a variety of stealth, platforming, grappling, sliding, destructible cover, swiming area's (that can be used for stealth in a great way).
- AI. the AI, specially on Hard mode is a bitch. those bastards are tough, and they try to flank you and use their great numbers to their advantage. if you stay still you are doomed, because they will surround you. they force you to stay on the move, which helps other aspects of the gameplay kick in, like stealth, larger level desgin, platforming, the grapling hook and melee.
- Friendly AI, Uncharted always had friendly AI, but in UC4 they really are the best and most useful.
- More dynamic set peices are there as well, the jeep chase is the biggest example.
sure the cover mechanices feel the same as UC2/UC3 to a large degree, but UC4 does a lot more and adds a lot of features to add a lot of layers to the gameplay.
Everything you mention really sound like evolution to the current UC formula. I agree with your points but when all is said and done, UC4 plays like a UC game with improvements to its mechanics. This would probably be the same for Gears 4. It looks like Gears gameplay and we know there are improvements to its mechanic but the developer definitely isn't going to mess with the core mechanics then it wouldn't be gears. Same goes for Halo 5 etc.