I haven't read the Essentials Kit, so I can't respond to how well RotFM implements that structure. Here's what I can say about why this didn't work for us.Re: RotFM, I haven't read it, but from what I've read about it it seems like they were trying to take the quest structure from the essentials kit in order to create a sandbox with lots of player choice and moving, interacting parts. Do people dislike this structure (preferring a more linear plot), or is it that the quests themselves were not enjoyable?
1) The BBEG and situation in Icewind Dale is so terrible that no good-aligned party will want to aimlessly wander through a frozen wasteland to explore when the entire region has devolved into cannibalism, human sacrifice, and starvation.
2) The quests present no tangible rewards. There are no magic items, not even decent mundane treasure. My players are 6th level and the fighter couldn't even afford breastplate without me handwaving the cost.
3) The encounters are badly designed. They are deadly or so easy there's little reason to do it.
4) The Ten Towns are all presented with next to no information. Even the largest towns have only 2-3 places detailed.
So if the point of the adventure was to locate a lost treasure in a hidden city, then that works for sandbox style play. Having a metaplot about an evil goddess destroying all life with a curse, that's something that needs a linear framework. RotFM wants both and succeeds at neither.