Support units can't protect them from butterfly mines,mortar area attack,artillery attack,aircraft attack,sniper...so on....
If ace sniper have support,german sniper can kill them without any problems,and will use retreat,saving his life,and causing an enormous hole in russian economy in one strike.
Very simple is also with butterfly =>just drop them over his head and will die surely without much worries...and other example,how i told....
I liked them first,but after some time i was realized is no worth to chose this doctrine just for having sniper ace.
Is to expensive for his job and chance of survival against human player.Can be good against computer,but human player kill them fast without many problems,and that manpower hurt allot.Recruit them three or four times after he die, on small or medium maps,and you will have no manpower for other units.