Indeed, this is a real immersion breaker. I'd like to either see every single lootable item actually lootable, and without any effort, or flag them all as not lootable instead. Making an item lootable and requiring one to walk around and dance for 10 minutes, climb on furniture or something might be fun in a Nintendo game but it's a humongous immersion breaker in a game like The Witcher 3. I've had to do death defying feats and actually get killed a few times to loot some containers, while others are not lootable at all.
On Skellige in the town just outside the fortress where Crach lives (I think that's his name, forget the name of the town but it's where you first meet up with Yennifer and have fun on the unicorn), there are several huts there which have this mega long bookshelf by the beds and in every hut that has one, the bookshelf is unhindered, no objects in the way you can walk right up to it. Witcher vision says it is lootable - but walking anywhere near it from any angle including jumping on top of it just does not work. That's one huge area of weakness in The Witcher 3 IMHO. In Skyrim you occasionally find an item that is normally lootable and it is not flagged as lootable so you can't touch it, but other than that - anything flagged lootable in Skyrim you can easily loot with zero dancing around.
Another problem which I just encountered again about 10 minutes ago is when something is flagged lootable and is visible on screen but right near the edges of the screen, either on the top or bottom of the screen, you can actually visibly see "[E] Loot" on the item but the E key does absolutely nothing and you have to walk around to make the entire object visible. The way I see it the game logic already determined that the object is lootable, and told me this by displaying it on the screen. Remember that and actually let me loot it - without a dance.
Another issue is when there are multiple lootable objects stacked on top of each other whether they are directly touching or separated such as a bookshelf on the floor that is lootable and a shelf mounted on the wall at eye level. The only way you can loot the shelf in 90% of these scenarios is if there is a table/stove/person'shead or something to climb on to get higher so the game engine recognizes the shelf. Annoying.
If a lootable object is visible on screen anywhere period whether it is centered on the screen or not, simply build a list of lootable objects and estimate which one is center target if desired and offer that one up first, but as geralt's head turns adjust to other objects, and if someone pounds the loot key, simply jump to the next nearest object. If even a fraction of the object is visible and showing the lootable glow, then make sure it is on the loot list. The way it works now you can see a back barrel in a pile of barrels but not loot it because other barrels are behind it. Also those big crates are terrible all over Novigrad docks and in houses etc. Notoriously hard to dance and loot.
if (object.lootable == TRUE && object.visible == ON_SCREEN && i_can_see_it ) {
let_me_friggen_loot_it();
} else {
break_immersion();
}