ZOTT garbage began 7 years ago, but Weasel was around for some time after that
When you think about it, the characters had to be busier than electric rabbits on speed, but what could've been exciting, action packed sequence was spread over seven years of tedium. The only good thing Shueisha seems to have done on this thing was the insistence to alter the word "Psycho" into something else, giving Kishiro a legal excuse to bail out of the contract.
You're right... the ZOTT arc did go on for too long... what was in plot time, was about 7 days, in our universe was about 7 years... you should now reread the ZOTT arc... without that 7 year wait, it seems much more coherent and interesting...
Ok... what I am going to do now is try to defend the undefendable... the ZOTT arc... knowing that a lot of people hate it...
I'll begin saying that I am pissed that ZOTT has gone longer than the original manga... especially considerering that in-universe, the plot of the original manga (Hyper Future Vision) occupies 15 years... while the ZOTT lasts a week... yeah, anyone see the problem?
That being said, I must say that:
1. The idea of Alita participating a Solar System Combat Tournament already appeared in the Playstation game... so the ZOTT was going to appear anyway..
2. Kishiro used the ZOTT to create characters based on the drawings summited in that Drawing Contest... he somewhat had that obligation...
3. Kishiro used the ZOTT, and the Space Saga as a whole, to create and explore the Gunnm universe without cheap, shallow, and boring exposition... instead, he introduces and develops the society and solar-politics... the conflicts between the planet-states, the Cold War between Jupiter and Venus, with Earth and Mars in the middle... the power struggle of Mbadi and how he uses the Zott to maintain the status quo... he introduces a lot of cool and/or interesting characters that participate in the ZOTT, or uses it to develop characters like Sechs.. we explore the dangers of methuselyzation and how it cheapens life... how the Earth emerged from a cataclysmic impact winter that wiped out most of humanity..
We even have an arc within the ZOTT arc: how Alita infiltrates Melchizedek to rescue her friend, and the Vampire arc...
4. Kishiro did make the ZOTT feel epic, with the Space Angels fighting against the Solar powers, against the status quo and societal control, and for the freedom and salvation of Earth... He made it that Alita, Sechs and the others were fighting for something historical, how they somehow changed the history and the society of the space population...
Or how Desty Nova, the most interesting character in the series, succeeded in his research in Karmatron Dynamics with Alita.
His goal was to free mankind from the shackles of karma (and free himself from being just a simple experiment, lab rat, or pawn of LADDER) and allow man to fulfill his greatest potentials. To eliminate their karmic restriction and "let everybody fly with their own wings," i.e. act independently and assertively in order to realize and exercise the full extent of their own strength. Of course, it's at the price of of gruesome and ultimately destructive experiments.
Rarely does he act to restrain characters, and most of the time acts to augment their imperfect bodies in order to fully realize what he believes to be a perfect psyche and will (this runs the full gamut of characters from Makaku, to Jashugan, to Den, to Zapan, to Sechs, even to Alita when she doesn't immediately threaten him). He intended to create a Nietzschean Ubermensch of sorts, and release it on the world.
Nova only acts as an adversary to Alita when she attempts to stop his experiments or thwart his plans, but even then he's revived her, reluctant to waste what he believes to be an incredibly strong human being.
Eventually, Imaginos Alita is the final product of his experiments... and we see how that "Karmic Anomaly" was able to change Earth, and now Space, through the power of will... Winning the ZOTT is the culmination of this.
You get a sense of accomplishment after reading Gunnm, beginning with Ido rescueing Alita from the scrapheap and suffering amnesia, with the culmination of her winning the Zott, and, in the process, defeating the Solar powers, destroying the control LADDER's pseudo-dictator Mbadi had, and saving Earth...
Ok, so it's like every other shonen... but it was well executed... just too damn long...