It was a jarring change. TNG Alexander was just a typical boy trying to win his fathers approval while also reacting as you'd expect to said father's many letdowns and abandonments. DS9 Alexander was a whiny emo faggot. Which kind of undid all of their TNG development because it seemed the message they were going for during it was that Worf was afraid Alexander would turn out exactly like he did unless he toughed him up and instilled Klingonness in him. At the end of the arc though they showed that those fears were misplaced and he came to accept that letting Alexander find his own place in the world didn't mean he would turn out to be a sniveling turd because he had inner strength that Worf was missing. Then DS9 comes around and it turns out oh no wait actually Worf was totally right to be terrified that Alexander was turning into a bitch and should have sent him off to that Klingon torture school.