User blog comment:Omega natsu2/Episode 176: The Dragon King, Review./@comment-24536822-20140406155427/@comment-4829046-20140406180447

Personal preference. I myself prefer a story to be split when they change their approaches. FT hasn't changed so it is fine but Naruto clearly did.Post-timeskip was clearly in a different league from pre-timeskip, in the part where they were all early teens, there was no Aktasuki plot, we only got Itachi and Kisame appear as an introduction. Dragon Ball signifies the original series where there were no named alien races or planet busting or aliens from all over the universe congregating on Earth for some reason, so splitting it into Z was perfectly alright. I wanted them to do so for One Piece but those goddamn mother****ing pieces of donkey**** pissed me off by not doing that. >:( I could only take so much before I dropped the OP anime.

So while I do agree that it's the same story, we need an obvious difference between them. Same applies to all anime. How else do we differentiate between them without mixing up the numbers?