As many stated , balanced power levels. Do you remember those chills Rock lee vs gaara gave ? When Byakugan was the "eye that sees everything" while sharingan was the " eye that copies"? When people got stronger by physical practice and not going around and stealing dead people's eyes? When Yondaime was rarely mentioned and his face was always hidden? When readers actually had respect for Iruka and he wasn't the first troll target after tenten and ramen guy? When few akatsuki were revealed and seemed like monstrous invincible criminals and now hidan for example isn't even top 30?When Naruto learnt with difficulty the rasengan that stressed his arm and threw people miles away, and then after hard training managed to create rasenshuriken, which damaged his arm severely (now he goes around spamming rasen shurikens and creating dozens of clones with making yoga-ball sized rasengans without even sweating)? When tobi was a good boy? When Naruto got 1-4 tail cloak due to anger and going in awesome rampages? When you could be a really powerful shinobi no matter your clan, dojutsu, dna or being a jinchuriki(name one current top 10 character that doesn't have one of these). I could keep going all day

, but we must adapt to changes. The manga/anime is still awesome just it is starting to get near dbz level, while it used to be more toned down.