It's no secret that the Juggernaut, aka Cain Marko. If the Hulk is already stronger than anyone else, would the powers of the Juggernaut really make him much stronger?
While he has never matched the outright strength of the Hulk, the magically imbued powers of the Juggernaut do have one huge advantage the Hulk could utilize: speed. More specifically, magic momentum. The Hulk can already be considered an immovable object, but what would happen if he were also an unstoppable force?
The magical power of the Juggernaut makes it so that once he picks up speed, he literally cannot be stopped. This magic momentum means the is essentially always running unimpeded and always picking up speed. During his time as the Juggernaut, the X-Men's Colossus was once clocked in at hitting 600 mph in Uncanny X-Men #543 from Kieron Gillen and Greg Land, drawing near to the speed of sound. While the Hulk can traverse large distances with huge leaps, and is most certainly faster than an average person, he would not generally be considered a "fast" superhero. With the power of the Juggernaut, the Hulk would indeed become even more powerful and unstoppable.
As the Avatar of Cyttorak on Earth, the Juggernaut's mission is to cause as much destruction as possible in the god's name. It's an ongoing objective that is easy to fulfil with the power of the Juggernaut, though Cain Marko often seeks to resist the influence of the god. As we saw during Colossus' time as the Juggernaut, the more destruction the Juggernaut causes, the more power is bestowed upon him by Cyttorak. If the Hulk is known for one thing, it's destruction. And assuming the Hulk in question is a more monstrous version of himself and not one controlled by Bruce Banner, the influence of Cyttorak would almost certainly drive him to cause even more destruction than ever, thus being granted more power.
The Hulk, who at times has already been known as a World-Breaker, would receive a huge boost to his power as he caused more and more destruction as the Juggernaut. Becoming magically unstoppable would already be a huge boon by itself, but his destructive nature creates the possibility of gaining even more strength from Cyttorak. If the Hulk ever acquires the Crimson Gem, the Marvel universe had better watch out.
