If you increase the party size by 50% then you are goin to need to increase the difficulty of most fights by either adding more combatants or increasing their levels. More combats and more hit points will increase turn length. That isn’t a narrative, it is irrefutably true.
Whether the turns become too long or not is purely subjective.
Having barrels in your inventory explode would be terribly unfun. That will just lead to reloading for most people. I’d be fine with making them much heavier, though.
