GT had a real strong vision early on during it's conception and drafting stages which we can reverse engineer since unlike Toriyama's flying by the seed of his pants approach. Toei is a production company with a discernible method to emulate Toriyama's writing. It's how they created many fan favorite Dragon Ball stories from across DB and DBZ. Again, GT was intended to be the culmination and finale to this continuity.
It had the goal to tie up as many loose plot threads and fulfill as many character arcs as possible, but ironically doing these things half heartedly led to the perception that it was this incompetent cash grab of a series coasting off of nostalgia and brand recognition.
But GT doesn't stand for Goku Time like many believe, it stands for Grand Tour which suggests it wanted to tour the Dragon World and ALL it had to offer before pushing it into a new age of Dragon Ball stories as set up for what we would later come to know as Modern Dragon Ball.
The reason why we failed to get the idealized GT vision that was pitched, greenlit and was the skeleton of the GT story that was eventually produced was because of the very nature of the production and the time it came out in. Unlike Dragon Ball and Dragon Ball Z, there was no tested source material to ADAPT and scaffold original stories around. GT was this untested and untried concept like many other tv shows that needed time to figure out what worked and what didn't. They would quickly make compromises to their vision depending on what was or wasn't well received. These growing pains normally are a good thing in most productions, but for something like GT it ultimately hurt the story
It's like an author who can't fully commit to their vision either out of a lack of faith or pragmatism. Choosing to keep the core parts of the story and getting rid of the rest. Goku's story was definitely rushed and for from being executed perfectly, but it ultimately was fulfilled by GT's 64 episode run. Goku's purity was refined until he reached transcendance and GT even ended with him watching over his and Vegeta's reincarnations. Goku jr and Vegeta jr. (Yes they are more than mere descendants, it's implied heavily during the Hero's Legacy special)
The closest comparison of the era I can make to the GT we received vs the GT we were intended to receive is Chrono Trigger. The main story of Chrono Trigger is a real basic time travel story to save the world from Lavos, but the reason what elevated the game and the story were all of the sidequests that fleshed out the journey, the characters and even provided alternate endings and a more fully realized gaming experience. In fact, games like Chrono Trigger and Dragon Quest games 1-6 were models of inspiration for GT.
The Grand Tour wanted to push and innovate the franchise even further by making the cast more introspective and broaden their horizons. The reason for this is because that is what the brand of Dragon Ball had always done. GT is a story around Self-Discovery and Hopeful themes.
From fights becoming more coordinated team ups, to adding in more Tokusatsu influence with the Power Ranger phenomenon in the West and trying to build a bridge to hop on the magical girl boom with their enlarged female cast.
Toei created GT as an allegory for Post Bubble Japan aka The Lost Decade. The bubble economy with it's endless inflation and debts came crashing down hard leaving Japan in a really bad state. Toei made comparisons to Japan's unsustainable escalation business model of the bubble era to the unsustainable story escalation within Dragon Ball and Dragon Ball Z. This was nothing new for Toei's studios as they love to place allegorical stories within their works. For GT specifically was to show how to form a sustainable community. In fact, each saga of GT has real world counterparts and you can even find missing stories that were cut out of GT due to production constraints. (I have found at least 2 missing sagas and more fleshed out versions of existing stories of GT)
Contraints such as the Skeleton Crew that were leftover to work on GT. After DBZ ended, the staff were scattered across to other projects. Leaving GT's staff without many of the fight choreographers to create the fights Dragon Ball was known for having. The tight deadlines and schedules didn't help with burn out either, but the passion is still there in GT's fights even if they were working with far less than they previously had. From creative energy attacks, to sound design, to crisper art, etc. But the shortcuts could not bridge the gap of the carefully curated fights of it's predecessors.
Eventually, to maintain viewership, GT had to continuously cut corners and cut content just to complete their vision in some shape or form. Since they accomplished that much, GT was likely deemed a commercial success, even if barely, but they weren't feeling experimental after such a disaster of a production moving onto safer storytelling as it yielded better reception.
So yes, the fan reading of GT having great concepts but a rushed and poor execution were correct. The original skeleton and bones of the story drafted in pre-production is much stronger narrative continuation of the franchise.
I avoided getting into anything too specific in this post as it was dragging on, but if anyone has questions, I might dig into them as well