3. Most Of Their Enemies Are Terrible
If Batman has one of the best rogues galleries in comic books, the X-Men sit at the very opposite of that spectrum. How many classic X-Men villains can you name off the top of your head? Now, don't name any that weren't in the films. See? Besides, like, Magneto and Mystique, there's a paucity of good X-adversaries. Mr Sinister is one of the most enduring, but he's also pretty indefensibly terrible, with his weird painted-on soul patch and GWAR-style costume. The Sentinels are fun Wolverine fodder, but they're rarely much of a threat, and look kinda goofy and dated. Nimrod is called Nimrod, totally unironically. The bad guys the X-Men face are either cliché supervillains, kinda useless, or just way too powerful to be in any way interesting, as is the case with Apocalypse. What's Apocalypse's deal? He can do basically anything. He's all-powerful. He's bloody boring, isn't he.