I agree with this.
This is part of the design of utility having high value potential, but having its downsides.
In the same way her rifle damage has many disadvantages surrounding it, other aspects of her kit also do this. IMO that is the idea of balance when you have high value potential from her utility or rifle damage, but there certain drawbacks and things to exploit when it comes to Ana’s kit, & her rifle.
Widowmakers hook is strictly for mobility & sniper angles while she has 6 targets to dps. Ana has 11 targets & is a different story on what her rifle & utility is. How it works, how its strong, and how its exploitable. Ana is about pre-planning before things happen, decision making, and multi-tasking alongside positioning for 11 targets.
I think sleep dart is fine.