I posted this on the old forums, but I thought I'd rekindle the discussion here.
I am considering adding an extra half action to the character's action allotment for the round. The reason for this is because it has worked nicely in WFRP and might address a few issues I have with DH. What is obvious is that the combat rounds in DH are very condensed, i.e. they span only a few seconds. That means that taking defensive action (i.e. moving into cover) has a higher "cost" relative to taking offensive action (i.e. shooting).
I've played a few games as a player, and it's been my observation that PCs and NPCs tend to remain in the same position firing their weapons or chopping away at the enemy regardless of risk. Moving into cover takes time during which you achieve nothing (surviving is an intangible benefit, after all), while squeezing off a couple of extra shots may be just the thing you need to score a lucky hit.
Ironically, once one has achieved cover one tends to stick to it, meaning that making a move to another position simply isn't done when doing so would require you to end your turn in the open.
I believe adding an additional half action will make for a more dynamic tactical experience since the characters can opt to make a move without this costing them the opportunity to attack. Also, if the characters can cover more ground then a larger combat area is more acceptable, thus making firearm ranges an issue to be considered.
-K