The Bren Gun should be left alone, honestly. It's great as it is. I can equip one at maximum and have an extra slot for picking up spare weapons. Plus equipping only one was something I did often even before this mod so I like the improved Bren as a result.
The weapon was designed to have a slow rate of fire in order to be more accurate so it's a great weapon for Infantry Sections in the Trenches. Lowering their accuracy at long range would destroy it's ability to be a defensive weapon. Infantry Sections simply are not suited for moving in closer to the enemy, due to their moving accuracy and shouldn't be forced to operate in that manner just to make their "Upgrade" useful. I also don't want to see them get fired on the move since that is a unique trait for the Commandos only. Need a more mobile LMG platform? Get an upgraded Universal Carrier and you have it. Please, no BAR-like Bren Guns!
The current Tommies play is rather boring. You can just leave them in cover/garrison on a sector and they can beat 1vs1 most enemy infantries that try to attack them, forcing to use more than 1 infantry to dislodge in which case they simply retreat.
Imo by changing the bren one could makes Tommies play allot more interesting. The balance could look abit like this:
Grenadiers vs Tommies (4)
Tommies (equal cover) advantage long range slight, disadvantage close range
Tommies (no cover) disadvantage
LMG Grenadiers vs Tommies (5)
Tommies (equal cover) slight advantage long range
Tommies (no cover) disadvantage
g43 Grenadier vs Tommies (5) bren
Tommies (equal cover) slight disadvantage long range, slight advantage mid range
g43 Grenadier vs Tommies (5) 2 bren
Tommies (equal cover) disadvantage long range, advantage mid range
The idea is the exact opposite of what you describe. Tommies are forced to move to make the bren upgrade useful, it is the bren upgrade that gives the player the option to use Tommies as more as a static unit if he chooses to.
In addition A moving a blod is limited by the fact that their DPS is lowered and they also have to move to cover to reach full potential DPS.
As for the Vickers K, I tried it with the changes and I wasn't impressed. The Vickers K was made as Britain's answer to the LMG42. You wouldn't know that by looking at it in game right now. If it really had to be redesigned, I would make it more like the MG42. It's fast firing rate (Comparable to MG42 in real life) would mean great short range, decent mid range and terrible long range DPS.
The Vickers K was actually developed for airplanes and for land was mostly used on the jeeps of desert rats. In real life it did not fire faster than MG42. As most mgs they are not very good at close range due to size and weight.
We should think of it as a LMG made for the Offense. Non-Doctrine Heavy Sappers get this LMG but they also have Sten Guns that are only good at short range so maybe it was intended for offense? Make the Vickers K suited for close range combat and that will be it's distinct purpose. Could merely just need a drop in long range accuracy and a longer burst at short range.
Heavy sapper can hardy be used offensively due to speed penalties. In game lmg have a distinctive weapon dps curve and totally reversing it in case of Vickers-K make little sense.