Carrying even more ammo than standard shouldn’t be… Standard…? Who is it that needs extra ammo…?
Snipers, assaulters, MG gunners, riflemen with SF rifles. In other words, specialists, people with high combat potential with their dedicated weapon who benefit disproportionally from being able to use their weapon for longer.
A rifleman with a standard bolt-action rifle, though…? He’s not a specialist, BAs don’t have high-combat potential in the same ways as the above example. If people feel like ammo bags are the best thing they could have for a regular rifleman, well then the devs have not made a very flexible class of soldier, which frankly they certainly should be (they are in BR III and IV, after all).
Then you could bring in extra health packs for survivability, or tools to repair friendly tanks you’re escorting (or both!). Pick up a grenade bag and use riflemen as psuedo shock-troops, very WW1, (grenade a room, grenade a room twice for good luck, then charge in with bayonets for King and Country).
This would actually be a way more compelling and interesting battlefield dynamic than what BR I and II currently have, simply by giving more leeway into what direction you want to go with your riflemen (by not making “simply having more ammo” so obviously the best option).
I have a friend, we play a lot together (BR III, but he only has BAs), he struggles with aiming, ammo bags for his riflemen are mandatory.
Frankly, I feel the same pull but for the opposite reason, I can actually land my shots fairly well, this means though that I feel the lack of ammo even more. Using semi-auto rifles have rewarded my good aim, I can do more with 50 rounds of semi-auto than I ever could with 25-30 of bolt-action shots. (CQC is unbeatable too, compared to BAs).
I made a whole-sale switch of all my guys from bolt-actions to semi-autos quite some time ago, I have not regreted it since. Oh, and I never use ammo bags on semi-auto rifles, not needed the same way as on BAs.