Modifying accuracy penalties would not be fine.
Imcreasing the penalty would make small arms fire even more insignificant.
Reducing them would make cover even less useful than it already is.
This depends on how you approach it. Remember game programs are an abstract representation of reality, simulations reducing that abstraction as much as possible.
With this in mind, analyze how it is in real life: Soldiers miss, A LOT. In fact, more than 90% of the ammunition spent in combat is off target. However, damage is such, that a single hit on the enemy will most likely take him out of combat.
Now, I am not saying CoH should be modeled on that. The "semi real" but arcade feel of company of heroes stems from the fact that shots can miss (unlike most other RTS games), but units don't die from a single shot.
On to the point: If soldiers miss a lot, then damage must be used to compensate or else, like you mentioned, combat will be long and tedious. Right now, small arms combat is a little longer than we like, because of the three factors we have been discussing: accuracy, armor and damage. Three different filters just to register a kill, which will not kill the enemy squad outright.
There's several ways the devs can approach this, and each one has its traits and flaws:
-Decrease accuracy, increase damage: This would promote close distance encounters, and cover would have to help more against damage, than to accuracy penalties (since units already miss more). Armor can remain the same.
-Increase accuracy, leave damage the same: More hits will register against the enemy, so perhaps armor would have to be raised slightly to balance it and allow a saving grace so soldiers don't drop like flies. Cover becomes extremely important then, because anything that will help your units get shot less, no matter how big or small, is elemental.
-Accuracy remains the same, armor remains the same, damage increased: Combat becomes more lethal, shots already hit relatively often and you have armor to save you in case they do. If shots pass armor, your men can only take about 2-4 shots each. Cover can become important only if the accuracy penalties are increased, or if they provide substantial damage reduction.
This is relevant to the bulletins topic since, whatever changes they choose to make (if they make them at all) will affect how bulletins interact with the game. In some cases for good, in others not so good (for instance, if damage is increased, the 4% health buff becomes less useful).
Something that has not even been considered, is changing how cover interacts with the game. Perhaps heavy cover could, instead of reducing damage, could improve armor instead. This has a synergy with the flamethrower theory: it works against cover since it ignores armor.