I would also look at the BattleGroup Kursk, Overlord, etc series of rules. In my opinion they model pinning very well. In particular going for area direct fire as a deliberate option can usually only result in pinning the target, but is very easily administered, no observation required and so on. Only if a ‘1D6’ is thrown on the target’s cover save is a single casualty caused. The gamble however comes in the end phase of the active player’s move – he has to decide if and how many pinned units to attempt to unpin…For every D6 number of units (sections/squad/AFV) he unpins, he has to draw a chit which has a random number that reduces his overall Battle Group Rating. Once down to zero – game over!
It works well in my view, and tends to reduce direct small arms fire to very close range attacks around assaults, most infantry fire in BG games is now dedicated to ‘brassing up’ a suspect enemy position to achieve suppression, entirely authentically I think.
'Blessed are the peacekeepers, for they shall need to be well 'ard'