He was the Klingon specialist on TNG, yes, but also responsible for the likes of Family (aka the one after the Borg two parter, where Picard goes home to recuperate from being Locutus, aka the first Trek episode to break with the "next episode: everything as it used to be" principle), Tapestry (aka the one where Q lets Picard relive his youth and the two end up in bed together at one point) and Yesterday's Enterprise (aka the one where everything is as in DS9 season 6 and 7 during the Dominion war, only it's TNG season 3).