The more Samson changes, the more he stays the same... or something like that. Change and stasis (non-change) are two big, oppositional pulls that, confusingly, both seem to be at work in this story. On the one hand, everyone who visits Samson is totally freaking out because "He's so different!!!" And they're right. But, considering how many changes Samson has undergone, it's never entirely clear that he's really absorbed the lessons. And that's really the big question of Samson Agonistes: does Samson's final choice show that he's grown and changed—or does it show he hasn't learned anything at all?
Samson's antagonistic interaction with the giant Harapha just goes to show he hasn't changed at all—he's just a big, strong, glorified bully.
Samson is definitely wiser than he was in the beginning, because he's spent the entire poem thinking through his own actions and reactions.