I don't think the storyline will change.
There will be new weapons, monsters, map platforms.
The caches will probably still be there.
The mission will remain the same, but will be different.
Of course, the gameplay will not be familiar (new)
And of course the atmosphere of the game (tempered, the sound of the zone will be different)
The game will be tense when you go through some dungeons (like laboratory X8 in Pripyat)
We will still hear (the Character) walking and will probably add the sound of hunger and fatigue.
Panel: the backpack will still be the same, but (food, drinks and medicine will be different)
In general, the toy will be a class because we have been waiting for it for so long, (And we thought that it would not come out)