I'm more scared of Singed running at me than Volibear. +A dissertation on Juggernauts as a whole.
is weak. That's no secret. But beyond being weak currently, even when the meta is favorable to him, he doesn't invoke a feeling of oncoming danger a giant bear in power armor should. Even in a setting with ghosts and demons, the idea of an electric super bear should be an intimidating presence, but he doesn't reach those moments in actual gameplay, even when he has two move in his kit dedicated to blasting into people at full speed and tearing them apart.
Volibear is a juggernaut, and I think the other characters in his class can be looked at to see some common trends that set them apart from divers like
.

These are the characters to which I refer when looking for common trends.
is also a juggernaut, and Cho'Gath is an odd case since he has chain cc, but otherwise there is a common throughline for this class that sets them apart from other melee damage dealers and tanks.
Wardens, like
, have a common thread of preventing the enemy from getting in
Divers, like
, have a common thread of having tools to get in and deal heavy damage with some crowd control
Vangards, like
, have the common thread of having tools to get in and lock targets down with crowd control
Skirmishers, like
, have the common thread of getting in and dealing heavy sustained damage to single targets
Melee Assassins,
etc, have the common thread of getting in and out with heavy burst damage to single targets
Now, the dueling power of each of these classes differs between each character, but in general, Juggernauts have the best combination of damage and defenses, with Wardens coming in close behind, having lower offenses but usually greater defenses. Following wardens, and beating them in trades, are the skirmishers, built for long fights with the tankier characters. The divers, vanguards, and assassins, have a kind of rock-paper-scissors relationship, with vanguards beating assassins, assassins taking out divers, and divers (usually) chunking vanguards with a combination of armor pen and focused damage.
So with the key defining features of the melee classes as put forth thus far combined with the hierarchy of their dueling power, it leads me back to my list of juggernauts above. If a diver is to a vanguard, both diving in but one focused on preventing the enemy from acting and the other on dealing damage, then a juggernaut is to a warden.
A warden's job is to prevent the enemy from getting in Thus, with the juggernauts above we can see a common thread of preventing the enemy from getting away
has a silence to prevent dashes, tenacity to shrug off roots meant to buy his enemy time, and a speed boost of his own.
's main gimmick is running people down with cleavers
's E minigame raises a catch 22 of stay and eat shit or run and get punished for it
and so on.
The point being this class has a tendency to have light cc in the form of strong slows or pulls (
to a degree) meant to keep the enemy next to them. They say "Fight me. Don't run. We're fucking fighting." Darius reinforces this further with his Q being much stronger when an opponent tries to get away from his pull.
And then let's look at Volibear himself. He has a speed burst with his Q, which also has a handy throw behind attached to keep enemies close, and a slow from his E. Finally his W and R are dueling tools buffing his auto attacks. So he has the makings for a good representation of a juggernaut. His passive even rewards him for sticking through long duels with its life regen.
The problem is just as the title and opening say though. He just doesn't command the kind of respect he should, and when he is good it is usually a result of just power leveling ahead of his jungling competition rather than a result of his kit itself being strong for dueling in lane or in ganks.
I have my own thoughts on some changes that could be made to the bear, but don't want to make this thread an advertisement for my own balancing whims. I'd rather see your thoughts on him. If there is enough interest I'll put down my ideas for him later.

and
, one change could be to his Q to make it a marking system.