The topic is not what's easy or hard. It's what fun and/or well designed. But yes, I noticed whenever maps are discussed it always boils down to how hard or easy it is that influences most players if they enjoy it or not (ie. if it's too hard it sucks, if it's too easy it's super awesomw-o- tastic-co!!!! ... le sigh
).
Liked your post just for that. 
IDK that you understand this yet. But honestly map dislike boils down to a few factors: 1)If that map comes up a lot in map selected lobbies for farming. 2)If the map causes extensive issues with gameplay.
1)Condor- disliked because of ammo boxes, general glitches, inability to load.
2)Goddess- disliked because of general glitches, frame drop, etc
3)Rio-dislike because of the box of shame, farming, etc
4)Hydra- disliked because of the dam farming strategy people used by being outside the map.
5)Giant- disliked because it's easy to farm. High prevalence in set lobbies.
6)FBW old version- was absolutely ****** despised because it came up in two out of every three searches; no **** BW had stats that FBW was 70% of gold completions at one time during the peak of Geth farming.
IMO it's not just the design but the actual ability of a system to actually run the map. Jos Hendriks spoke on here about Condor and how much he loved the design of the level and if you take out all the glitches and other **** it's actually a great map. He wanted to add vertical elements and add things that weren't available in other maps. That succeeded but the ability of the system to actually load and run that map failed.