hmm, i think he still is.
he's a master at genjutsu, and it seems like not a whole lot of shinobis are good at escaping that. and his susanoo with the infinit shield and sword that seals is powerful. he's a force to be reckon with.
He was in the top 5 during all of part and throughout most of Shippuden. I think he lost his position once we got a glimpse at Madara's and Hashirama's powers, Sasuke gained the EMS as well as when Naruto gained KM/BM. I think he was still in top 3 before all of that happened, right beneath Tobi and Pain/Nagato.
My question is when did he stop being top 5?
Hes the only dude who hasnt lost a fight i can think of and would have surpassed madara easily if he did not die of illness same goes for minato. It seems all the top tier ninja die while weaklings remain