Goku getting turned into a kid wasn't the main reason people didn't like the show.
Put simply, the show had no soul. By this, I mean that there was a lot of pointless stuff for the sake of being pointless. As for why these exist, that's pretty simple: they weren't meant to be pointless, but instead they were trying to channel the spirit of Dragon Ball. DB was adventurous and fun, and by dialing Goku back and using the novice Pan and engineer Trunks, they would be given the freedom to go on wacky and zany adventures like the old days...right?
Well...not really. Because Goku was still capable of destroying worlds, and Pan and Trunks, were pretty damn strong. Apart from that, it didn't really draw from anything. Dragon Ball was a story that was based off of the Chinese epic "The Journey to the West" (or Saiyuki, in Japanese). This is important, because this presents the backbone for why Dragon Ball set out to be so adventurous in the first place. It was a zany (if not serious at times) romp filled with mythologies and the like, headed by a cast of diverse characters. And there's the biggest problem: the characters.
I'm not gonna sit here and say that Dragon Ball as a series has the greatest characters, because I don't believe that to be the case, but by God...in GT I just don't care. Really, I don't know how they did it, but the characters in GT- which have had years of development and establishment- are just so downright boring, largely due to most of the main cast's relegation to the bench, but even Goku, Pan (oh God, Pan), and Trunks are boring in this, and Giru.
Giru, please.
Giru stop, I beg of you.
And I think this is the case because Dragon Ball GT- in pretty much every way- never had a solid idea of exactly what it wanted to be. It was supposed to be some sort of combination of Dragon Ball and Dragon Ball Z, and that was very easily apparent, but was it one? Well...it tried to be. But its two greatest faults in this were that it both left out some of the key things that made these shows what they were and that there was quite the dissonance when trying to blend the two. In the case of the former, it had the adventuring of Dragon Ball, but it didn't try to invoke the sense of discovery and new that you got simply by watching the opening to Dragon Ball. New characters? What are those? Mysteries, Legends, and aesthetically interesting locations? Well, we got planets with plot convenient characteristics and the concrete jungle of Earth, so there's that. Zany and cookey misadventures that still grant a sense of progression in some sense? Well...
yeah, let's go with that.
In that sense, it will have caught the eye of Dragon Ball fans, but their fancy? Eh...well, they might watch to see how it ends. In the case of the latter, it has the fights, but you aren't really given any reason to care except maybe in the case of Baby. Possibly. But the problem with Baby is that his story
already happened once. But the difference between Baby, a character with a tragic backstory and a somewhat justifiable reason for doing what he does and, say, Frieza, a character with absolutely no past and that just enslaves people for muks and gigs is that, in the case of the latter, I care about what's at stake.
I mean, the idea that Baby will revive the Tuffle race through the Saiyans is pretty dark and twisted, I'll give it that, but...who is
this? What is this thing? They cease to exist if he succeeds? Oh...why should I care? Last I checked, that man in the second picture only had about a scene in this show, and
Gohan Goten in the first pic was still riding off of the coattails of what Toriyama wrote at the end of Z. But where's the character? I know I spent time with these characters in Z, but the Vegeta of GT is not the Vegeta of Z. These characters have changed, but when you show snippets of personality but never ultimately cultivate actual ones, how am I to get invested? In Z, when Vegeta is done in by Frieza, it hurts. It hurts because we followed this character on a journey, and watched him slowly change all the while clinging to his pride to the very end. But I never felt anything like that in GT. I don't know GT Vegeta, and I've yet to see a reason why Pan dying would be anything other than unfortunate. In GT, they seem more like players in the story rather than the sculptors of it, and in execution, especially here, it doesn't work out well.
As for the other point...eh, I've been rambling. But I'll just say that there are a number of times where the show tries to be adventurous like DB and, for the sake of it, makes the characters seem a lot weaker and less able than they actually are because plot convenience, which can take the viewer out of the show if they know how much the characters are actually capable of, which goes back to my original point of pointlessness. Things happening only to try to emulate the spirit of adventure without successfully conjuring it.