Do you know WHY the cheapest infantry get that weapon? Its because they are and only ever will be 4 men. They have that weapon so that despite their small squad size they can continue to fight as without it dps falls by 25% per model (of whom are easier to hit AND more expensive to replace than tommies btw) tommies dont have that problem becauae they can diffuse the 4 man squad problem.
I think weapon racks and 5 man squads should be mutually exclusive. If thats the case keep brens big and strong, but as long as they get throw on another model (with health, a gun and presenting another target to disperse incoming damage) theres no reason for the bren to be MUCH more than a fancy model.you cant have an inferiour squad inferiour 100% of the time in literally every single way and call it balance. Let okw start with obers and lets see how that balance goes. Same thing, just a smaller scale with tommies.
You're taking the design by the wrong end, Brit Tommies are designed to be 5men squad from start thus their expensive price from start. In order to balance them early game, they've been reduce to 4men squad. If Tommies were meant to be 4men squad per design at that same price, Ostheer sniper and mortar would have received the hammer nerf slam at Brit release (which would have broken SOV/OST matchup).
There is no magic here, You can't have Gren and volks at the same level than Rifle and Tommies because of price and faction design. Dual weapon for Rifles and Tommies are meant to be soft cap and give Gren and Volks some mid-game advantages before USF/UKF being able to dual equip all their squads.