With the Avengers and X-Men having now reached higher power levels than ever before, Marvel needs to be wary of the pitfalls of power creep. The term power creep originated in games that are intended to provide perpetual experiences, primarily affecting tabletop games, collectible card games, and video game MMORPGs. Games introduce higher and higher power levels through updates to keep players engaged and spending money. The problem is that as the power levels creep up, the older content becomes underpowered and obsolete.
Power levels creep up in other forms of media as well, notably manga and anime. Manga and anime often follow one character over a long period of time. In order to overcome their antagonists, they become stronger and stronger as they face stronger and stronger enemies. Powers levels often become astronomical and can be comical when compared to where the character began. A clear example is the Dragon Ball series that started with Goku fighting in a tournament of primarily humans to taking on a literal god of destruction.
The teams in multiple Marvel series are now experiencing power creep. The X-Men started out as a group of mutant students who regularly fought against Magneto and battled bigoted viewpoints. Now the X-Men have unlocked immortality, forced humanity to accept Krakoa as a world power, and declared themselves rulers of the solar system. The Avengers team was originally comprised of Thor, Ant-Man, Wasp, Iron Man, and the Hulk. Although that is a powerful team, it pales in comparison to the current team, members of which now possess both the reality-warping Phoenix Force and the potentially infinite power of the Star Brand.
As opposed to the more mythic scope of DC's Justice League, Marvel's teams have leaned towards being more grounded. Marvel gained momentum by attempting to represent "the world outside your window". Although the astronomical power levels of the current X-Men and Avengers can make for some novel stories, Marvel should be mindful to return their teams to a more grounded level to avoid some potential pitfalls of power creep.
One issue with the teams' power levels having crept up is that the antagonist has to match their power to pose any threat at all. This will also often lead to villains nearly taking over the planet or being a threat to all of life to even be relevant. It now takes a cabal of devils from multiple universes or the rewriting of history itself to even rise to the level of the Avengers. When the stakes are always so excessively large and not grounded, it can be harder for readers to relate or feel the weight of the stakes. It is also difficult to feel like any stakes are truly worthy of being elevated to the level of an "event". When the entire planet is being taken over by Khonshu in a single arc of Avengers, it's difficult to justify other planetary takeovers as an "event".
The larger problem is that when stories lose their footing in the real world, meaningful messages can be lost. The X-Men were always seen as an allegory for civil rights and human rights movements. That has been lost in the age of Krakoa. In fact, if the allegory still applied, the current state of the X-Men on Krakoa would be every bigot's nightmare come true. Marvel has always made it clear that coexistence is the X-Men's goal, not to promote segregation and racial superiority. With the power creep their teams are experiencing, Marvel is getting further away from the elements that brought them so much success. Although these elevated power levels can make for interesting and unique stories for a short time, the Avengers and X-Men should return to ground level to avoid the pitfalls of power creep.