The Vanishing Phase

There's something that bothers me a little about Warhammer 40K; the way the units can sometimes do a lot more than usual in the same time frame. For example; take two identical units. One moves and shoots, and that's all it can do that game turn. The other moves, shoots, then makes an assault move, then strikes blows in both player turns.

It's actually a lot more extreme than that. Let's consider how far a unit can move in one turn. First of all, let's say they are normal infantry, not jump or bike troops, so no special movement ability, just guys on foot. Now let's say they are Space Marines with ATSKNF, who were falling back last turn. They start by regrouping, which allows them to make a 3" move. ATSKNF allows them act as normal this turn, so they move, shoot, then assault - a maximum of 18" of movement. During the assault they can make 3" pile-in moves, if they lose they fall back at most 12" (let's say they were moving towards their own table edge from the beginning to keep things simple). Now if they get assaulted they can again potentially make 3" pile-in moves, and can fall back up to another 12" if they lose. This means that, unlikely as it is, according to the rules an individual model can move up to 51" (3" consolidation + 6" move + 12" assault + 3" pile-in + 12" fall back + 3" pile-in + 12" fall back) in a single game turn, while an identical model that didn't happen to be close enough to an enemy unit can move 12" at most, and that's by sacrificing their shooting.

So how is it that one unit was able to move over 4 times as far, and do so much more, than the other identical unit over the same time frame? What's the first unit doing while the second one was so busy? The conclusion is that there's a huge inconsistency in how much a unit is capable of achieving during a game turn. Is this a bad thing? Not really, the game has been developed and tweaked and balanced over many years to work in a certain way. It just seems strange when you think about; how we claim those two scenarios took the same amount of time?

My point is, I sometimes think this "vanishing" assault phase is strange. Personally it makes sense to me to combine the shooting and assault phases into a single "action" phase, and completely remove charging into assault, instead if you end your normal move in base contact you've just charged into assault. That way you have either a shooting phase or an assault phase, and the distance you move doesn't change unless you run in the action phase. Would this play better on the tabletop? Maybe not, there's certainly issues to be worked out and I'm afraid it might lead games to be pure shooting matches by weakening the assault phase, but perhaps with other tweaks it could work?

I always suspected that in 5th edition you were basically supposed to be able to either shoot or assault, as you couldn't assault after shooting some weapons (or running), and it was only special rules or circumstances that would have the "unusual effect" of allowing it. But with the current abundance of assault weapons and pistols, and the increased potential charge distance, plus overwatch in your opponent's turn, the assault phase in 6th edition just has the potential to add so much activity, or none at all.