One of the biggest draws of the Dragon Ball series is the various level-ups and forms the characters take on when they encounter a strong new opponent. It all began back during the Frieza Saga when Goku achieved Super Saiyan for the first time, and since then there have been numerous variations to this level. The latest level in the franchise -- Super Saiyan Blue from Dragon Ball Super -- has fans less than thrilled, however.
Super Saiyan Blue is the result of using godly energy to reach the Super Saiyan level, causing that energy to fuse with and increase the user's natural ki output to that of a deity. The form can only be achieved through rigorous training with a deity or by absorbing a deity's power, then turning Super Saiyan. Despite how powerful this sounds in theory, many fans feel it's underwhelming to say the least.
In a Quora post, user Jimi Afolabi talks about how Super Saiyan Blue is useless and simply a recolor of the standard Super Saiyan form. It goes into detail about how Goku and Vegeta have lost most of the fights they used the form in, from Goku's fight with Jiren to the fight with Fused Zamasu to Vegeta's fight with Hit. Not once did the form help them defeat their opponents. The design is lacks any interesting features beyond the blue color.
Reddit user u/lol_VEVO posed the question as to why people liked the form, with answers varying from people liking the color to the meaning behind it to how it looked when combined with the Kaio-Ken. Others mirrored the OP's disinterest in the form and how simple it is compared to other transformations. Posters also voiced their distaste for how only Vegeta and Goku are achieving new forms while their children are being left out. Still, others like the Super Saiyan Blue's minimalism and how tame it is compared to SSJ3 and 4. Other posters don't feel strongly either way and are neutral to Blue's existence within the canon.
There have been numerous posts on a variety of platforms mirroring these sentiments, but the overall consensus seems that while Super Saiyan Blue looks nice, it's lackluster in terms of power. Some have criticized how much Goku and Vegeta have relied on the form in their fights, rather than only using it as a last resort against a more powerful opponent. When they do use it, it feels like they are no more powerful than they are in the Super Saiyan God form. One use of the form that's been a point of contingency is when Goku used it in a fight against Krillin, who is known for not being the strongest fighter in the group. There's a reason he's considered a joke in the fandom.
So while the idea of using godly ki to power up is great in concept, the execution with Super Saiyan Blue has left much to be desired. Fans agree that while the color looks nice, the way the characters heavy reliance on it undermines the entire idea of having this deity-esque ability. Pair that with how lackluster it appears in terms of power increase and it makes sense why there's a divide on whether it was even necessary in the first place. Hopefully, with the upcoming fight against Granolah, the shortcomings of Super Saiyan Blue will be addressed.