The enhanced targeting mode on the smart pistol does reduce the lock on window size. It says so in the description.
But extended mag reducing accuracy? Eh... sounds like a bad trade off and a poor result overall to have less accuracy. But slightly longer reload time sounds fair and makes sense since you are attaching a larger mag.
Ahh your right on the enhanced targeting (last time I read it was release so forgot about the last part of the description), so it does have a negative in taking it over factory mode - my bad.
As for increased reload time increase on extended mag instead of less accuracy, that actually sounds better and would kinda make sense.
Nah because it gives you an incentive to do the challenges and unlock the attachments.
You would still have the incentive, I'm suggesting that each mod has a positive effect and to compensate has a negative effect over factory mode (so all modes are worth choosing including factory mode). Most mods already do this (have a + and a -), but some mods don't (they only have a +) and its just a case of using factory mode until you get to it, as once you do there is no point in using factory mode anymore - extended mag is one of these mods, it has only a positive and no negative, so its a case of using factory mode until you unlock it, because it has all the stats of factory mode but with more bullets.
Take the Carbine for example, it has 3 modes - factory, suppressor and extended mag,
The Suppressor lowers damage over factory mode but the weapon makes it so you don't appear on the map and you make less noise, so you choose between more damage/noise (factory) and stealth (suppressor). The extended mag is the same as factory mode expect with more ammo in the clip, with this mode you don't choose anything (you get the factory mode base weapon but with more bullets) - so you only use factory until you unlock it, after that, there is no point in ever using factory mode.