This is, unfortunately, one of the difficult things about any poll like this.
If someone says they dislike a class, they might do so for thematic reasons, mechanical ones, or both. The Artificer unfortunately tends to get hit from people on both sides: those who like it conceptually often find it lackluster, and those who dislike its theme couldn't really care less if it's functional or not.
Most of my responses were on the mechanics front, but some verge into thematic elements as well. I dislike the Wizard because the class has no flavor. There's nothing in it except the spells--you don't even meaningfully research anything. That's thematic, but it also comes from a desire to have theme represented in mechanics.