Game Design #30: Coherency & Leadership Ranges

Soldiers in a squad must stay within 2"of each other* 

I could copy and paste this into almost ANY platoon-level game and this statement would be correct - that's how universally this rule is used.

But why?
Well, it's a simple, handy way to ensure individually-based models stick together and act as a unit.
It's an abstraction.

What if we break coherency?
If one of our mini soldiers moves beyond that magic 2" (which is about 4 metres, to scale) what happens?

Usually one (or more) of these:
*The soldier must spend their next move to get back into coherency
*The unit's next move must restore coherency 
---or more drastically--

*The soldier must make a morale test; if it fails it flees the board
*The soldier cannot attack or take any action until it rejoins the unit

There's a lot of "must" there.  It assumes a trained professional soldier will somehow break down if he is more than a few yards from his companions, and not attached via an invisible umbilical cord.

Yes, a soldier will be more effective working in close proximity with team mates - it's easier to communicate and co ordinate attacks. Yes, he will be more confident with his buddies beside him.

But is there a need for "musts?" - perhaps giving a -1 modifier to attack and defence (simulating better target awareness/mutual defence) would encourage players to keep units together.

Why 2" range? (I'm tempted to say Warhammer did it once then everyone else copied.)  Is it the range someone could shout to each other in a firefight?   Why 2"and why not 12"?  Why not simply "line of sight?"  What is the "footprint" of  a fire team - how much area does a "fire team" spread out to cover?  40-50 yards?   Isn't there a "minimum distance between troops?"  I'm presuming about 10 yards.  You'd assume a single grenade would take out most of a Bolt Action squad*, for example.

(*Naturally, the historical game Bolt Action uses a gap of under 1" so the models are practically holding hands. It then does away with template weapons. Perfectly logical. )

Leadership Range
Another common rule is leaders having a radius (usually between 6 to 12") where they can influence troops; i.e. remove suppression, rally fleeing troops, or perhaps issue orders if it is that style of game.
 Again, I'd ask - why x distance?   And why is this radius larger than 2" if that is the maximum distance squads can shout at...  do lieutenants have louder voices?  unless we are using *drumroll* radios....  Which leads me to question:

Why do we even need coherency?
Most of the games that use the 2" coherency mechanic tend to be "modern" or sci fi.  You know, around the time this device called the radio came into fashion? 

Obviously we want squads and fire teams to act in a co-ordinated manner, and not have individual troops scattered all over the board, but I don't think a hard limit is needed. Keeping friendlies in sight is important, and coherency should be desirable, but I question that it needs to be forced artificially.

Coherency in Company Level Games
I don't play these very extensively, but the few I own tend to have squads in coherency with their platoon HQ, and platoon HQs within coherency range of their company HQ, and so on up.

Ranges & Scale
Yes, I know the 1" gap between models could actually stand for 25 yards.  But it's the ratio that interests me. If we use 1"= 25 yards coherency range, it needs to be checked against other ranges - a rifle which shoots 300 yards might have only a 12"range (!) and grenades might only be able to hit one model at a time.  Abstracting the scale too radically impacts things like model basing and the size of buildings as well.   

TL:DR
The purpose of this article isn't that the standard 2"coherency rules are bad; but to question what seems to be (like true-line-of-sight) an almost set-in-stone wargaming convention.

I'd like to know designers are basing their decisions against gameplay choices, or actual ranges, or something - not just copying something cos it is just the "done thing." 

*Is 2"the best distance? What do we base this on? What is its ratio vs other distances in the game?
*Should a "leader's" range differ from this? How long should that range be?
*Should units be forced to move into cohesion?
*What is a suitable "penalty" for troops who move out of cohesion?
*Is cohesion needed at all, and if so, for what genres?