The character abilities and combat of the original Mass Effect trilogy revolve around six classes. There are three pillars of combat upon which these classes are built: Biotics, Combat, and Tech. Three classes primarily focus on one of those pillars, while the remaining three utilize two for a hybrid approach. Each class has its advantages, and each are a viable way of playing Mass Effect, but it appears that the Engineer - the Tech specialist - is the least popular class among ME Legendary Edition players.
In theory, Mass Effect's engineer class plays a primarily supportive role in combat. The Engineer's abilities focus on weakening enemies, while buffing squadmates. Because of their role as battlefield managers, Engineers were only proficient with pistols in ME1, and could only wear light armor, though their arsenal was expanded slightly in the sequels. The first Mass Effect gave Engineers the added benefit of being able to bypass locked containers and encrypted devices outside of combat, but they weren't the only class with that ability.
It has now come to light that the Engineer was the least popular class in the Legendary Edition, chosen by only five percent of players, according to the Mass Effect Twitter account. Accompanying a jab at Mass Effect's Keeper scanning quest on the Citadel, the tweet's infographic also shows a series of interesting trivia, including most popular ME1 squadmates, how the community was split on some of the games' major decisions, and how many Commander Shepards decided to punch a reporter.
The Problem With Mass Effect's Engineer May Actually Be Tech Abilities
The lack of popularity in the Engineer class may not be a problem solely involving the Engineer, but with the Tech abilities themselves being undesirable. Immediately above the Engineer's last place finish is Mass Effect's Sentinel class, being selected by only eight percent of players. The Sentinel splits its specialties between Tech and Biotic powers, meaning players in general may just be uninterested in the whole Tech branch of combat techniques. Many players who picked up the Legendary Edition were returning Mass Effect veterans, so it wouldn't be surprising if the Engineer class has always been the least popular. Many newcomers might have seen the description of the Engineer class and thought its less aggressive approach didn't befit Commander Shepard, too.
There's likely no single reason the Engineer ended up in last place. While it can certainly be considered the least combat effective, all six classes are viable options, and the Engineer especially is enticing for ME3's Insanity difficulty. The game's default selection is Soldier, which happens to be the most popular at 40 percent, so it's possible that played a part. It seems that the most likely explanation for Engineer being the least popular Mass Effect class is the most mundane and uninformative - for one reason or another, its description and abilities were not enticing to Legendary Edition players.