Dave Cockrum, who was an artist for DC’s Legion of Super-Heroes, came over to Marvel in the mid-70s and did a pastiche of that group for the revitalized X-Men called The Imperial Guard. As powerful as that group was, they came off as nearly incompetent as the Legion.
Cockrum had in fact created Nightcrawler, a star of the new X-Men, as a Legion member, but the editors at DC nixed it. One man’s trash…