I have a player who wants to try a Sniper Operative, which clearly has a focus on Stealth and presumably shooting from stealth.
However, reading the Aim action, it says nothing about interactions with the hidden state. Given the rules under the Hide and Sneak actions, any action (which Aim is) that is not Hide, Sneak or Step breaks hidden and makes you observed.
Is this intended?
Similarly, interact actions to activate a Sniper Scope or reload a Sniper rifle will also remove the hidden condition, which makes a Snipe and hide sequence extremely awkward, and looks like its simply going to devolve into an Aim, Shoot Sniper Rifle, and Reload+Stride (via Mobile Reload) sequence every turn in order to simply use the sniper rifle for its 1 shot per turn, and never actually interact with Stealth.
Anyone else have experience GMing or running a Sniper Operative?
Nope, that is not intended.
The hidden condition (or it might be the Hide skill) has a section about unobtrusive actions not breaking stealth, as per GM discretion. Despite what it says, this part is in no way optional if you want your players to not hate you.
Aiming and activating a scope fall under this exception, no question. Reloading is a little more tricky, but a sniper will almost certainly have learned to operate their weapon reasonably quietly. Anything else would also break the whole thing, as all snipers only have 1 shot, as you pointed out. So any sane GM should apply the exception here as well.