I wouldn't have a problem with this. Right now sniper rifles are a joke, most longarms are better.The only benefit of a sniper rifle is its range, but combat in SF normally don't take place over hundreds of feet.
Also the damage of a sniper rifle is ridiculous, a level 13 sniper does 4 to 40 damage (av. 24).
A level 13 NSC has 190 to 225 hp, so you need around ~ 8 shots to kill it with a sniper rifle. That didn't sound very "sniper" to me.
With trick attack this level 13 sniper would do 12 to 94 damage, still no one shot, but definitly a little more intressting.
Another idea would be to grant the sniper rifle a general damage bonus, if the player use one round to aim.
Basic shot = one shot/round, normal damage
Aimed shot = one shot every two rounds, damage x 2.5 (or so)
This would also transport the fantasy of a sniper without making it overpowered.
Yeah, Snipers are kinda just "Why though?" Weapons, which is frustrating because it takes up 1/3 of the Operative's proficiencies. Even more so when you figure Mechanics, Soldiers, and even Technomancers can be better snipers. Mechanics with Overcharge and an energy sniper can add 4d6 or even 7d6 damage, or you can add the Energetic Fusion to a kinetic sniper to make it use batteries and still add a respectable amount of damage to a sniper rifle. Soldiers can just reduce their penalties to negligible values and add a good bit of damage with sniper multishots. And Technomancers can just become The Bulletwitch and snipe with 14d20 Disintegrates or just massive AoE fireballs with Spellshot. And meanwhile Operatives are over here like "I can turn off their flashlight, or make them a little slower for a bit!" It's kinda BS