I don't think anyone's complaint about the barrels is that people shouldn't be able to plan carefully and set up the battlefield a little bit. If you want to do cool things, that's great!

One problem is that the barrels are currently the -only- way to do this. It would be so much cooler if, instead of generic exploding barrels that outshine the things the characters can do on their own, if we could actually utilize each class' skillset to create interesting and varied traps that are designed for the situation. Let the ranger dig pit traps and fill them with spikes or snakes or something. Let the rogue set up trip wires and attach them to that spare crossbow to fire at people as they walk through the door. Let the wizard create magic runes that summon in giant boulders to fall on the heads of whoever steps on the rune. Let the fighter weaken the base of a wall and then push it over on some enemies when they pass by. Let the trickster cleric create an illusion to draw enemies into those traps.

There are so many cool things that you could do that can make the classes shine -and- make each battle feel different because you have to customize your traps to the environment. If you can just drop a bunch of exploding barrels into any battle, it makes all characters feel the same and all battles feel the same.