One of the things I love about 4e is how easy it is to customize monsters. Not just in terms of changing power keywords, adjusting levels, or wholesale swapping of powers, but fundamental monster modification. For example in the PHB3 Game Day scenario (spoiler alert) there’s a white dragon stuck in icy walls of a cave. Instead of the normal white dragon powers, this dragon had powers specific to being stuck in that cave. In particular it could bang on the wall and rain down deadly icicles. Maybe this is a re-skin of the breath power, but the example is meant to illustrate that it is easy to customize and tailor monsters for single purpose encounters. When done right this can really enhance the encounter. It also adds a bit of freshness, i.e. not all white dragons are going to be exactly the same. This monotony of monster was common in earlier editions. The tricky part is to make sure there is still consistency and the monster retains its racial essence, otherwise game world gets confusing and hard to relate to.
Can such encounter-specific powers be applied to player characters? I’m thinking not. Players have to versatile enough to handle situation thrown at them. Maybe a barbarian has a rage power that knocks down stuff from the ceiling onto enemies in a burst, but that would require a lot of indoor encounters. Instead characters could get special magical items that have specific powers (a hammer of icy thundering, in the white dragon case) that is only useful in ice cave situations. Alternatively each encounter could have terrain powers: for example, an icy pillar could allow for an athletics checks to knock it down. This gives a the character an extra choice for a particular encounter without having to be built specifically to take advantage of it.
The nice thing about the terrain power philosophy is that it opens the door for use of an athletic or acrobatic stunt in any situation. Can you turn throwing a table into a burst attack? Who knows? But another nice thing about 4e is that there are tables of level appropriate damage. For example, if I were the DM, I’d say a character could pick up a table as a move action and throw it as a standard as a close blast 2 with an Athletics vs Reflex check for low damage on the table on page 185 of DMG. It took less than half a minute for me to come up with that ruling. It doesn’t matter much to me if there are already rules that potentially cover that, or that there might be a better way to rule it, as long as the player doesn’t make a habit of throwing tables. If it does come up again and again, I’d probably invest in researching the mechanic, but for a one time situation it’s easier to rule quickly and move on.
But I’m getting off the point, which is that almost any encounter provides a player with an opportunity to do something unique in that situation. In the ideal situation you have a feat that is applicable or the DM has constructed a terrain that you can activate against the enemies AND he’s told you about it. But there is not something the DM has made available, we should always be thinking about how we can use the terrain to our advantage: knocking stuff over, moving ladders, throwing tapestries, creating a cave-in, etc. Even the most open-looking fields can have hidden dips and ditches to knock people into or hide behind.
It’s not something I’m used to thinking about, but it’s never been so easy to improvise.