One of the standout Marvel characters to shine in the MCU's 2014 Guardians of the Galaxy movie was Rocket Raccoon, in his big-screen debut. Accompanied by the tremendous voice work of Bradley Cooper, audiences fell in love with the scrappy raccoon with a heart that was bigger than his stature. The fact that Rocket Raccoon was literally a small raccoon actually turned out to be a key detail in his personality. This may be a small detail that's easy to overlook because it's been such a key feature to who Rocket Raccoon is in the comics for many years, but those same comics reflect just how badly Marvel Studios could have gone in a completely different direction for the character.
During the Guardians of the Galaxy crossover with the X-Men, titled Black Vortex, fans caught a glimpse of each character on each team's cosmic potential thanks to the titular artifact. Unlike some of the other heroes, Rocket doesn't choose to embrace this form, but audiences do get to see Rocket Raccoon's cosmic form, which is that of a bear-esque humanoid creature.
As the MCU was still trying to get Guardians of the Galaxy off the ground during its pre-production stages, there was concern and debate from fans wondering if Marvel Studios would deem a talking raccoon too silly and instead make this big-screen interpretation something closer to a humanoid alien, a la Chewbacca in Star Wars. Thankfully, James Gunn and the rest of the movie's creative team nailed Rocket's look, but it's interesting to see fresh comic interpretations of Rocket Raccoon that reflect how he could have looked if fans' worries had come true. That's the case with Rocket's cosmic form, which turns him into a humanoid hero (albeit with a characteristically huge gun.)
As stated before, Rocket Raccoon being an actual raccoon is a key part of his personality. He hates being called a raccoon, be it as disrespect or in friendly jest. His disdain for it not only continues to be a running gag to this day but is a big reason why he is such a brash, cocky, hotheaded character seems to stem from his insecurity. Rather than being effectively just a furry Star-Lord, Rocket has to compensate for his size by letting his mouth, grit, and determination speak larger than words. It's this fact that will turn him into a legitimately legendary hero remembered far into Marvel's future.
Rocket doesn't seem to have those same personality traits when he does find his way into a humanoid form. Take, for example, Guardians of the Galaxy #14 by Al Ewing, Juan Frigeri, Federico Blee, and Cory Petit, where Rocket Raccoon swaps bodies with Doctor Doom. Almost instantly, Rocket gets a confidence boost and seems far more comfortable in Doom's body. It also helps that Rocket's penchant for violence made him a kid in a candy store with Doom's weaponry, but being able to look people in the eye or over their heads as opposed to up at them seems to have done a lot to adjust Rocket Raccoon's usually irascible attitude. While the humanoid look suits Rocket well, it's for the best that the MCU's Guardians of the Galaxy stayed loyal to the comics, keeping the diminutive, weapons-obsessed strategist as he was always intended to be.