TL;DR: This module suffered greatly from lazy writing. Lots of missed opportunity.
The story focused on raiding a dragon’s hoard, which wasn’t the most engaging story that could have been written. The contacts leading into the characters taking up the quest was lazy, so was the manner the characters were led to the Lizardfolk King and the hags. The NPC interactions were more-or-less “Hello let me tell you this piece of information because the plot requires you to know this now off you go”. A very linear module without much shining points.
There were also quite a few “plot holes” in the module. DDEX1-10 Tyranny in Phlan stated that Phlan was pretty much in lockdown after the Maimed Virulence has taken over, hence how the characters still managed to start the adventure in Phlan is a total mystery. Velvet was away from his lair because he went to meet with the Maimed Virulence, so are the characters supposed to have encountered Velvet when he flew in and landed in Phlan? The module also felt very out of place in the larger story arc of the rest of Season 1. The DMs know from the “Adventure Background” section that Velvet teamed up with the Cult of Dragons to transform into a Dracolich, but this connection was almost completely omitted in the module.
Also the final Dracolich fight was extremely underwhelming. Transforming into a Dracolich at 30 or less HP means that Velvet may well die within a turn or two after its transformation. Having no stat blocks for the Dracolich version of Velvet also made no sense. If Velvet isn’t behaving any differently in combat before and after the transformation, why bother?
Instead of having the characters being hired through plot convenience of having Velvet “away from home” and a random dwarf hiring them at the perfect timing for a raid, the ties between Velvet and the Dragon Cultists, alongside with the possibility of a Dracolich transformation ritual would have been a much stronger hook to lead the characters onto pursuing this quest. That would have risen the urgency of the matter at hand, tied this module with the rest of Season 1, and not a glorified “loot-run” that we’re now left with.