To be fair, the "exploring" of a raid really isnt a factor for most people A) because its already been heavily datamined beforehand, and Blizzard even doing previews showing the entire raid and all the bosses, and B) even if there was exploring to be done, that covers your first ever time through, and thats it.
Secondly, some of the 5mans had some amazing moments, including literally being chased by the LK himself, and unless playing with a guild, those dungeons absolutely offered a lot of challenge, at least in the short term. People have a habit of only remembering the flawless runs through with guildies they had and forgetting all the wipefests with pugs. HoR in particular was an absolute nightmare if all members of the team didnt know their roll and perform it well. PoS was a real PoS with inexperienced players as well.
I know a lot of people who absolutely loved the raid specifically for the reasons you hated it, so as you say, it really is quite subjective.