<<<scenario in Stalingrad could be good to reproduce the tense atmosphere of Enemy at the Gates - like each player only has one life.>>>
Sounds like a great idea, if there was like a 2 or 3 minute spawn protect. If it was that way, there would be spawn camping like maaaaaad.
What about teams? Axis vs Allies?
Also, you must remember that snipers are like FldOps, Eng, what ever, it takes skill. The immature and amature snipers are going to run around a lot and relocate, where as the expert snipers are going to find a spot and stick with it. 
Also, it would make it a much fair game, if snipers could be killed in one shot by any gun, so it would promote Sniper vs sniper wars instead of Sniper on Eng or FldOps. 
–Garrett