Maybe she's more dependent on sig than people are saying
The popular consensus now is that her sig is skippable if you have p3+ fusion comp (mine is p4), so decided to give her a 50/50 chance (I have m1 Miyabi so there's a bit of overlap, Velina will be a much bigger meta priority to my account) and won. She's cool and all, but I wonder how she will age at m0w0.
We currently have her shill boss and buff that give 40% abloom dmg and 30% ice dmg, both of those have almost no saturation in her base kit. Nangong fixes the second part, but Vivian doesn't. Unless there's a future abloom dmg focused support (which is not that unlikely), it can be a bit misleading to say now that her sig isn't a big damage increase. If you take those shill buffs away, it might be close to a 30% difference to a p1 FC, like what Alice has to her free options, even more against low def content.