They are fine imo.
1. Not central part of the meta in any game mode.
2. They break up the hated sandbag camping/double mg static frontline gameplay that so many people hate.
3. People who want them nerfed are mostly people who are incapable of using them themselves.
4. They create an interseting asymmetry where onen player has to be active constantly to avoid bleed and try to convert the lack of stopping power of his opponent into map control.
I am completely with you.
If it is Kimbo playing Wehr on Langres - ok, the sniper is nearly unkillable in a game like that.
In most other circumstances is rarely is the OP unit. Even in tournaments. Was it absused? It was not played often. That is a strong indicator.
Yes, Barton's 5Sniper play was awesome. But that was years ago
.
It is not built super often. And it is fun. I would love to leave it as is.