Bomb throwing, even just quick tap-throws without aiming, is way too slow. Geralt can efficiently draw his sword for a quick slice from almost any animation, but so often the delay on tapping the bomb button and when the actual thing launches is so disparate that often it whizzes right past enemies heads, or Geralt himself is caught in the blast because the moment of opportunity is long gone and the enemies are within melee range while the throw tracks its target super close. Just unreliable especially when trying to set up that perfect group hit against fast moving trash like Nekkers or Drowners. I use bombs regularly, but they consistently are a fumbling block in execution with their long delay time.
Yeah this is one of the few huge problems imo.
What's especially bad is that you can't roll and immediately throw a bomb. I'm used to games like AC or Batman, where you can roll and hold an aim button, and the character will segue straight into the aiming animation. But in TW3, you have to wait a full second or two after rolling before the game lets you aim a bomb.
This second or two is enough to get you killed if you're against a horde or fast, aggressive enemies like Drowners. Once you're in combat with them you basically have no chance to get a bomb out, short of using the terrible bomb-auto-aim which always throws bombs miles past your target.