Chest is where your most vital organs lie, which is the only " realistic" reason why it still has 1x damage. It's more to do with rewarding proper shot placement, I think most people already aim at the chest when shooting centre mass. So I can't see it being too detrimental to your average player overall.
You could make an argument that the inner thigh should be 1x as that's where the femoral artery lies. But I'd be such a small hit box that It'd have such a minimal impact on the TTK.
Syringe ideas are a step in the right direction, the problem with having two is that it thins out the loadout and overall flexibility of those who want to equip both.
Plus suppression is an incredibly weak mechanic in BF6 that having temporary immunity to it isn't all that amazing. If suppression also gave blurred vision, a minor tinnitus effect with reduced spacial sound volume and increased weapon sway / reduced ADS accuracy then It'd be a more impactful mechanic. In which having temporary immunity from would be greatly beneficial.
I'd be in favour of the small medical pouches having an instant self use function providing supports utility got split into two, an ammunition only training path and a healing only training path.
As beng able to use a small supply pouch instantly and being able to throw down the large ammunition/healing crate is getting really rather broken by that point.
But by splitting up the utility, so one training path has an instant heal and the healing crate. While the other has instant ammo and the ammunition crate is ok.
I think with the reduced incoming fire detection it'd have been with a suppressor and subsonic ammo combo only mechanic. Otherwise it'd be to strong.
Trade off could be subsonics and suppressor combo have reduced suppressive fire mechanics, which if suppression got a buff, would make it an interesting mechanics trade off.