There isn't a problem though. It's just another bitches' stone, a griper's standby when people need to gripe but can't find anything that's really worth griping about. Something that explodes after you shoot at it is a good thing to have in a shooter. And we have moved from having a single volatile, explosive item to stacking lots of these items together, and make them interact with the environment. It's shooter evolution at its absolutely finest, and only aggressively lame people complain about exploding barrels.
Sure, but don't make that one of the 'features' for you game.
And by problem I didn't exactly mean something wrong with them like the common usage of that word. It is more like "Oh, you just got knocked up, but you wanted to have a baby, so its not a problem". See what I mean?
Still, explosive barrels are overdone in some games and should be removed at times. I'm not saying from the entire game completely, but when they are out of place. Uncharted is a good example where explosive barrels were everywhere when it didn't make a lot of sense at all.