Dynamic combat

I was reading this thread on EN World. It is about how movement might be encouraged/more important in combat in D&D 4e.

I’m not going to speculate here on 4e mechanics, but this idea did get me to start thinking about how to encourage dynamic combat. Part of the goal is to get people to use their environment to their tactical advantage.

There are a few things you could do here. It would be helpful to have a few different kinds of terrain ratings (other than difficult). It would also help to have a Knowledge (Tactics) skill – or something like it. If you had these things you could institute rules of the following types:

When a character moves to a new square of Terrain Type X, she can make a Tactics roll as a swift action to gain a benefit for a single round. The DC of the check might depend upon the benefit. Benefits could range from +1 to attack rolls if flanking to gaining partial cover or a shield bonus from terrain features to a bonus on checks when defending against a bull rush… or other things. Class features might extend the duration of some of these benefits or (in the case of Marshall-types) allow you to make the check on behalf of an ally when they move… or obviate the need for a check at all in some cases.

Forcing an enemy to take a 5 ft step backwards might be another option that could be fun – what if, while on simple terrain and not flat-footed, you could avoid an attack that hits your AC exactly by taking a 5 ft step straight back? Or what if there was a “press attack” combat option where, if you hit, your opponent must make a Will save or step back 5 ft (allowing you to follow as a free action)… and doing so might allow your opponent to take half (or no) damage? (Making the will save would subject them to full damage).