My Take as a Jungler main of 6 years on why people don't find it Fun
Now I love jungle and reached D5 on it last season (Check Dead Unborn in LAN). I play about every champ that can jungle on it, but when playing ranked I exclusively pick Warwick and Rek'Sai, in that order (and the odd Rammus or Amumu when we really need a tank).
What do all those champs have in common? mechanically, they are extremely simple. If I ever try stuff like Lee Sin jungle I would probably be as useful as a potato. So what skills do I use to get to Diamond, and why do people not find those skill tests fun?
1.-Map Awareness:
Jungle is the roll that needs good map awareness and control the most. For most people, it isn't clear when you succeed at having good map awareness. Why? because you almost never have feedback on it. Just for reference, every time I walk between camp I am looking at the minimap instead of the screen, and between combo rotations on camps I look at the minimap again. That's how much map awareness is needed, and for a lot of people it is boring. However, you can easily but the opposite jungler half a level behind as soon as you see him fail a gank top and steal his grump and wolfs, but that kind of stuff isn't noted by the team/obvious to many players, so they don't find it fun
2.- Every Toxic Player blames your for losing lane:
We all know/have played with players who as soon as they died they start rationalizing why it isn't their fault they fucked up, and 80% of the time they will blame it on the jungler (for ADCs is 50/50). Many people find the constant harassment by team mates annoying enough that it drains the fun out of the role. Specially when you are doing something right (like pushing wave so enemy misses minions when both laners don't have TP) and they tilt off that
3.- About 50% of junglers' success depends on good routing:
It isn't fun for a lot of people who prefer having their success be determined by mechanical skill, and it isn't very intuitive probably for a lot of players because no one teaches you how to do it. However, a lot of junglers get ahead by knowing in which order to take camps, when to take camps and when to back/not back to minimize down time. The amount of times I have had 3 levels on the enemy jungler just by mixing ganks when my camps are on CD vs they leaving camps up to prioritize ganking is ridiculous
4.- This season is a lot more punishing when you are behind:
This season, when you are behind as a jungler you have to play off your teamates, mix split pushing and opportunistic counter jungling to get back in the game. This isn't how it previously was, and a lot of people are having difficulty catching up to the new meta. Also the win condition for when your mid laner feeds their ass of and you see the enemy mid laner having 4 levels on you is kind of rough
That is my take on it anyhow. Also as an overall there are many champs accross all roles that have become unplayable with how the game has evolved. I'm not giving Riot shit on it though, because the gameplay updates like Blitz's, Wukong's and Yi's shows Riot is working on fixing it