We didn't have "structural issues", we had consistency problems.
There are 2 separate things going on with Lily. Because of the setting style, it's not suitable for Ashas, CZ's, Moissanite, or any more delicate gemstones. It's fine for diamonds.
Second to this, our jeweler had trouble maintaining the proportions via CAD each time he'd tweak the design for a new center stone. It got to be very time consuming, for this particular design, to modify for each center stone. The additional design time rendered the setting not profitable at the price we were selling it for, so we opted to discontinue it (which may be permanent, may be temporary, we haven't yet decided) rather than increase the price.
To be honest, the general public showed little interest in the Lily setting in general, and the majority of inquiries were for sims, which we can't use in the setting anyway. So we thought discontinuing it for the time being would be best.
That being said, we didn't try modifying the design into a prong setting like Schubach's did for Milady's Lily. That would solve the sim issue, but I just haven't had the time or resources to resurrect Lily for a face lift