As a sniper, I wouldn't mind it if it made sense. Such as the sun hitting the lens but it shouldn't do it if you are hiding inside a room or hiding in the shadows. Even without the glint, there are a lot of ways to find us so the no revive head shot its probably the best change they have made (removes kill cam)
The only thing that I don't like is that the no revive head shot works with any gun recon uses, that should be an exclusive bolt action rifle or the DMR. Wouldn't mind trading it for faster reload as snipers shouldn't be playing the numbers game, Make every shot count. weight the consequences of firing a miss shot. (you better find somewhere else to hide like your life depends on it)
there should be dead give aways that there is a sniper like flash from you muzzle when you fire, which would make accessories so much more worth it, specially with the point system they have right now or if your buddy just drops for no reason. If you can't revive him use smoke, run for cover and check your flanks
Also I know how frustrating is to get shot out of nowhere but that psychological aspect is how snipers should be playing and if a sniper gets knifed from the back there should be a mechanic equally satisfying to relieve that frustration. (In real life snipers who got caught would experience hell to put it mildly). Not saying the game should repeat it but give an incentive to hunt us (extra points depending on how much dmg and kills we have)