GTAIV is the worst feeling AAA game I played the entire generation. I didn't like how it felt on day 1, and I grew to dislike it more and more since. Any HINT of that game in GTAV irks me to no end. After Max Payne 3, the control mechanics and animations in that game should've been Old Yellered by Rockstar North never to be seen, felt, or heard from again. The fact that there are remnants of it in GTAV is enough to dock a point in a review IMO. It's unacceptable.
As for the distance on the cover system: I find it just makes cover more cumbersome. I'll often try to take cover on a pillar, or some thin object and be magnetized to a fence, or another wall, or some random desk, or whatever the environment is. You can barely cut off the cover animation, then it takes ages (relative to combat speed) to get off that piece of cover before you lose half of your life. It's still a janky feeling system IMO. And in regards to the health system: The characters are so weak, and the enemies so accurate that regen barely does anything. Same for vests. Without any strong visual feedback, you go from fully healed to near death in the span of 3 seconds and die without getting to react, partly because the enemies are so lethally accurate and partly because the mechanics aren't up to snuff. I'm not even kidding when I say Red Dead Redemption felt more coherent and comfortable in combat. On top of that you still take incredible amounts of damage from everything to the point that I wonder why they even upped the level of crazy if they were still going to make the player so fragile.
But man, you seem to have enjoyed aspects of GTAIV's combat, so we'll never agree on this. I'm obviously in the minority as all the 10/10s and 12 million+ sales show you.