There were very few things I liked about GT. I don't completely hate it, I just dislike it. I loved the opening/ending themes and a lot of the ideas, but:
1) The setup for each saga was okay(except Super 17, which came out of nowhere), but they were handled poorly in my opinion. The concepts sound exciting, but it was just one big disappointment after another. I know they were trying to mimic the original DB, but the humor was bland and repetitive. It wasn't the same. I guess I liked some of the first episodes though, before Bebi showed up.
2) GT Trunks. 13 years and I still hate you for this, Toei. Haaaate.
3) New villains were boring, ugly, and unoriginal. You can only recycle personalities so much.
4) Speaking of repetitive.. I hope you like Goku, because he's the only character who accomplishes anything significant in this series.
6) Character designs. I liked Pan's, I think that's it.
7) Animation was horrible at certain points. The first few episodes looked great. Then this happened:
My only major non-aesthetic issue would be them NOT taking Vegeta with them into space. I mean; why on Earth would you leave the one guy who actually has experience traveling around in outer space, behind?!
Same. I thought that Vegeta would
want to go too.