Sounds good. Leave acid/cold/rot as the sole terrain of the elementalists, they should still have more elemental damage options than rangers.
As for the affliction effects, I think it would be best to just leave them out. As others have already pointed out, from a lore perspective it doesn't make much sense if a bullet can root someone. From a mechanic perspective, it just makes the ranged skill much harder to properly balance for too little gain.
Also, we already have a system for physical debuffs that is currently hardly used: The critical hit effects and the aim stanzas. Aim head (stun) is used often enough, but the other 5 are seriously lacking in comparison. Those effects are stamina drain for the body, slow attack for the arms, slow movement for the legs, parry penalty for the hands and dodge penalty for the feet. Why give the ranged skill afflictions to slow attack or slow movement, when it already has a way of inflicting those effects that nobody ever uses?
Expanding the critical hit system would be a much more simple and novel way to give rangers some debuff effects. You could introduce new stanzas or ammo stats that increase either the chance of getting a critical hit or the effect of the critical hit itself. You might even consider giving critical hits completely new effects, as some of the current effects are rather poor next to the afflictions.
I'm also against completely removing the ability to shoot on the run for launchers and autolaunchers. The ability to shoot while running is what gives ranged it's own unique experience and seperates it from magic.
Please, give some advantage for standing still while shooting, but don't make them completely unable to move. The ability to carry much more ammo at the cost of moving is ofcourse my favourite. But I wouldn't be opposed to expanding the "snipe" skill to work for autolaunchers and launchers either, so that they can simply do more damage if you stand still.
So much for what I don't like. What I really do like about the proposed changes:
The increased range on rifles, the "focus shot"/"snipe" skill, the cartridges concept, and a new range credit.
I'm not sure about the focus credit. I like the idea of a focus credit on certain special skills, with focus being unhealable that wouldn't be very different from having the skill on a timer. But I'm afraid a generic focus credit that can be used in any action instead of health/stamina credits would quickly make ranged too powerfull.