As someone who plays nearly all games with at least one Exo source if not two, I've been on the receiving end of golems many times. Yes, they are hard to deal with. But they aren't impossible, and sniper immunity will not make that huge a difference. Further, given how strong sniper turrets currently are, I don't see any need to make them even stronger. The easiest solution to exos is to get a superweapon before the first one hits. You have to push things, but I've been nearly always successful at getting something that can help me stop the first Exo. Once I do that, exos just get easier. With the new turrets though, a layered defense is perfectly capable of taking down a golem. Finding the right solution for your map is the key.