One would sure think so, but the problem with most challenges to statutes like this is that the legislature can enact just about anything so long as there is some "rational relationship" to a legitimate public purpose. The burden is on the plaintiffs in this case to show there is no such relationship. That's a difficult burden to sustain. So a judge may disagree with the law and sincerely believe that the legislature could have accomplished the same purpose by employing more effective or less draconian measures, but unfortunately that doesn't necessarily mean that the law won't be upheld. State courts have been traditionally reluctant to invalidate state statutes.
Nevertheless, I think the plaintiffs in this case have a good chance. One main point made in the Complaint is that there is no rational basis for imposing harsh restrictions on the manufacture of e-liquids intended for use in open systems while leaving e-liquids used in closed systems unregulated. For example, there is no evidence that the process of making open system e-liquids is any more likely to produce contaminated products that making liquids for closed systems. I suppose an argument can be made that once the liquid is sealed in a closed system it's less likely to become contaminated, but the statute doesn't really address that issue.
By the same token, why does a facility making open system e-liquids require extensive security measures, whereas one making closed system e-liquids doesn't? I can't see any reasonable basis for this distinction. Imposing these restrictions on open system products gives closed system products a huge competitive advantage.
The Complaint points out that the statute makes any open system e-liquid which isn't made under super high security and "clean room" standards illegal to sell in Indiana. This would effectively ban the sale of all open system e-liquids not made in Indiana. This would harm Indiana e-liquid retailers and distributors. I understand that there has been a companion case filed in federal district court. This may well be an unlawful restraint of trade among the states which a federal court could find to be invalid.
The Complaint also points out that there are several ill-defined or undefined terms in the statute, including "tobacco" and "ingredient." When key terms used in statutes aren't defined, or the definitions are ambiguous or nonsensical, the courts can declare the statute void for vagueness.
It will be interesting to see how this case progresses.
Something that keeps coming into mind for me is if we do win this case there's nothing to stop the legislators from simply amending the law to include closed systems. I'm afraid that may be what we end up with.