and frankly, you shouldn't be able to. If you wanna rush somebody, put a bullet in them on the way so they can flinch and you safely start a combo.
I'd argue just the opposite, that Hard mode forces you to be better utilize all the mechanics. You have to use those grenades, you have to prioritize enemies and better weapon drops to use on them, you have to know the environments, you have to stealth to take out SOME of the guards, you have to use the right weapon at the right time(snipers and explosives at a distance, pisotla/shotgun/sub-machine guns up close), you have to take advantage of whenever your NPC parter grabs a goon, you have to use cover and be careful of it being destroyed, you have to utilize your mobility to avoid gunfire, you have to be smart about your melees or rope swings...its mechanically the sharpest Uncharted yet, so play on a difficulty where you need to use them right.