as by my name you can tell i hate the dbgt for many reasons. 1st kid goku wtf. 2nd pilaf is dead from super buu's human extinction attack and dende only wished back good people. 3rd why didn't they use earth's dragonballs to wish the black stars back to earth and to fix goku. 4th if pan couldn't go super saiyan then how can her grandson who is only 1/6 saiyan. 5th goku leaves his family and friends to train with a dragon who is over 9000 times weaker than him (as proven in the king piccolo saga when piccolo kills shenron it implies that goku is stronger since he kills king piccolo). 6th piccolo's death was in vain since the writters forgot that he fused with nail, therefore, making him a different namekian than the kami before he split with piccolo (so the black star dragon balls should never have existed). 7th majin buu didn't have to fuse with uub to fight baby vegeta, they could have teamed up and baby wouldn't have stood a chance (i know mr satan told buu not to kill anymore i don't mean kill baby just make him leave vegeta's body like what goku did). 8th (and last even though i have more) everyone is weak except goku when in dbz everyone was strong.
so in short dbgt isn't a direct sequel to dbz since there is continuity and it sucks