Negligible as in, it only doubles the time taken. It still only increases the amount by about 2 maybe 2.3x. This is still an impossibly short period of time. Human reaction speed is only so much.
And yeah, policing human error isn't easy. However, there's really no perfect way to establish balance in a written competitive environment.
If you totally balance it, it restricts the writing.
If you try to balance it, it restricts the characters.
If you let it go free, it restricts competition.
Edit: Guns are fine at low tier too! They're fine at every tier because the viability of a weapon that only has a linear aim and narrow strike zone is limited, they're fine at every tier because the viability of a weapon used by a normal person or even a superhuman is limited only to the abilities of the user.
I've been incredibly successful at balancing the mechanics of items in many instances without restricting the writing at all or restricting characters.
Linear and narrow strike zone are not limiting factors at low tier when a singular, well placed shot can be lethal and can be actively pursued. This can be done in a singular post on any Arena that isn't specifically designed with countermeasures at appropriate distances to deal with such a character.
I do not establish balances based on the differences between writers. Assuming relatively equal skill, a particular weapon can be imbalanced in comparison to another.
So what we've established with me so far is that guns are fine assuming:
- The non gun wielding character has over 120 times the reaction speed of a normal human (I was being generous with the reaction times in favor of the non gun wielder in terms of requirement based on the complexity and required no actual stimulus).
- Is capable of accelerating over 2800 times faster than a sportscar (this was just to 60 mph which isn't fast enough to avoid the bullet from the calc I did)
- Is capable of moving at approximately 90 mph in order to dodge the bullet at a range of 10 feet with only a 2 inch required adjustment to avoid on a singular kill shot. I also did this calculation in favor of the powered melee/caster by doing the calculation on a dodge to the side. Any approaching momentum would reduce the time they had to deal with it an up the requirements.
You can get a touch more time by reacting to motions, but this also assumes the gun wielder has not augmentations of their own. However, the above would not be found on a low tier character AND the existence of a such a weapon actively restricts not only the viable combat options of others, but the places they much take place.
I understand no one has to fight a gun user, but please do not tell me that they are appropriate in lower tiers of combat. They are fine at higher tiers of power when there would be a wider range of acceptable powers that would not overwhelm others' powers capable of dealing with them. Otherwise they are overbearing and restricting to others.