Honestly I know this is a Dragon Ball forum but I consider Dragon Ball pretty mediocre compared to even other shounen like Fullmetal Alchemist. The story isn't terribly compelling, the characters are one dimensional, the story becomes formulaic and Part 2 looks wildly different to Part 1, which while I think both look good I would have preferred consistency. Toriyama has also admitted to not really thinking ahead and changing his story of a whim (17, 18, Cell etc are all due to his editors input) and he doesn't even remember very basic details of the world he created. Compare that to just about any other popular manga and mangaka I think Toriyama is probably average or below average. I think Monster is a million times better in every aspect I mentioned. Vinland Saga has better art and characters. Berserk and Vagabond also have better art and characters.
Berserk even by the end of the Golden Age looks wildly different than the first arc, much less the stuff after it. Artstyle change is the last thing to criticize a series over unless the art actually regressed to a lower or less detailed quality similar to YYH and (most of) Hunter x Hunter.
I also would say DB is less formulaic than many other popular franchises like Terminator and One Piece (another shonen) considering every Terminator movie basically takes place in the middle of a city where two guys from the future converge upon their intended target at the same time and a chase ensues in which the heroes try to survive, blow up a lab or both, and pretty much every OP arc follows a formula as repetitous as Pokemon.
If I had to name AT's main fault it would be that he was influenced by the "Kinnikuman/Hokuto no Ken generation" sts, which were almost as inconsistent as Bleach and just chose to take directions that were most popular with the readerbase rather than consistent to established facts or the narrative of the story, so he didn't bother to keep track of things that could potentially cause plot holes. And by the latter 13-ish volumes of the manga he'd just stopped giving a fuck and made cyborgs stronger than the tyrant of the universe and the Super Saiyan come out of an old guy's lab based on Saiyan arc data and made convoluted time travel that was nearly, again, Bleach tier in consistency. Along with much of the Boo arc just happening for no reason a la the Future Trunks arc of Super, where Boo split in two and spawned an evil version of himself that became stronger when re-fusing for no reason, turning to Kid Boo for no reason when the process was undone, the Kais backstory coming out nowhere for why he became Fatty and so on
But even with that he's a better storyteller than Kubo, Kishimoto, Mitsutoshi and Hiroya Oku combined