I don't think devs were thinking when they were making this weapon - it's impossible to fight against as a Raider.
Let's see:
By itself, it's an automatic shotgun better than Alicia's
The bridges it creates make constant killzones which you cannot breach due to the RIDICULOUS damage the spheres inflict, making it impossible to pass through the zone. The ability to revert their direction and capability of firing another one as soon as the first one disappears gives Valeria every advantage on the battlefield against no matter how many human opponents.
You can't beat it at range because Valeria has armor and those spheres pass and deal damage through walls
You can't approach Valeria because she can create a killzone at her own location, similar to H.I.V.E.'s health drain
What can you do? Lay down and die
Nerf it.

For the last few days I've been trying different raiders, trying to find relatively the best one for going antagonist mode. And it always turned out to be Hans.
I mean look at this: a guy with temporal invulnerability to melee, soaring in the air at great speeds, shooting down EXPLOSIVE projectiles (anyone who have ever played an FPS with rocket launcher in it knows that jumping makes shooting rockets way easier), has the fastest melee animation and finisher. Give him a rare weapon and he can wipe out the whole squad of bunched up raiders, which is the thing they must to do not get jumped on. They scatter - they die on their own because of the goddamn airstrike. Doesn't this call for a nerf?