While you might be tired of these "villains" that have some sort of "noble goal", but their approach is "wicked"; I find them much more interesting when they are EXECUTED RIGHT.
Orochimaru is much more of a "villain", but that does not make the situation/plot ANY better!
Orochimaru is power-hungry motherfu*cker that wills to do anything to achieve that power. He sometimes appeared as a person that simply "wants to master all jutsu", but it is also pretty obvious that he attempts to dominate people, considering his actions against Konoha, against Grass Country, and against his henchmen/Sasuke/Team.
He seeks nothing else, and disregards everything but his selfishness and own good.
You might say Madara is a shitty villain and that you hate all these tropes of "tragic villain" in Naruto, but that is imo 10x more fun to observe, than Orochimaru that has such a simplistic, but fairly realistic and believable goal/desire.
In other words, Orochimaru is boring as **** as a villain imo, and I would totally zone out if he was the "final boss". You can connect with Madara and read all this funny back-n-forth dialogue and philosophies behind human existence.
With Orochimaru, you won't get that dialogue or interaction. It would be simple as that----> Orochimaru needs to be fu*cking killed, he is a true, immoral, scumback, gogo Naruto/Sasuke,
EN FIN/ THE END