This group started by attacking everything they found. Head to head and with no thought. After the fourth encounter and second group of kobolds they retreated (carrying two of the five) out of the village found a vantage point and watched the cultists systematically loot and murder. They had two rogues and neither actually tried to hide let alone scout. In retrospect it was a mercy that they didn't try to make it to the keep. They might have tried to nick it.
In the entire, excruciating three hours of it (the first encounter, 2 cultists and 4 kobolds, took an hour!) I think I was asked what they could see twice, and both times it was because they wanted to know if they could see the dragon from the hill. Two of them had chosen one of their bonds to be having family in Greenest.
Having actually read the rules, one of them doesn't want to play because you can't get a sword higher than +3 (this is a 45 year old lawyer) and another is upset because one of the fighters wants to be a Eldritch Knight ( a thirty something mother of three who wants her wizard to be special).
Given all of that I really don't think the adventure was the problem.
Also, given the sample size, it could only be 0%, 33%, 67% or 100%. Not sure of your point there.
Was this Encounters, or a group of players who often played in the past together?
Regardless, D&D is meant to be fun. If a given group likes to attack bad guys, I don't see what the problem is unless HotDQ does not meet their needs.
As to the Eldritch Knight comment, there is a certain level of truth to that. It's hard for a Wizard to be special when Bards, Rogues, and Fighters can often have the same spells (let alone Sorcerers and Warlocks, but that is more understandable), but the Wizard has fewer hit points, lower AC, and weaker base attacks. Seriously. Both Rogues and Fighters can have the Shield spell. WTH? As limited as it is at a single round, the Shield spell is one of the best Oops spells in the game and the heavy hitter Rogues and Fighters can get it at fairly low level.
5E does have a lot of semi-spell caster elements to it that water down the low level pure spell casters a bit. Granted, as DM, you need to let your player know that this is a temporary situation. At about level 5 (about 26 encounters in), Wizards finally start to shine. She just has to bide her time (something that some players do not want to do and to some extent, justifiably so).