While I think surfaces themselves are ok, I do think they need to be less readily available as it is now.
Frankly, one may ask what's the point of playing something like Wizard, when your average meathead fighter can just toss explosive or oil barrel and do carnage on par with Fireball at will and every turn if he so desires, with all these countless barrels of wine/powder/whatever you can collect from everywhere and stock in camp.
I can understand when you have a specific big encounter with opportunity to drop some trash, like that
second fight at druid gate where you can blow up sappers and toss already placed 2 barrels down, which makes sense because it's siege preparation.
These kind of things ARE fine, when you have some explosive intended to be exploited in a specific encounter to help you a tad right there, where it makes sense and not overused everywhere.
But just being able to hoard barrels and toss them around willy nilly? That should be a no, IMO.
