>>7269400Because Goku spends a large portion of Dragon Ball and Z in the Turtle Gi. It ends up being very washed out as a design over time, especially when it's worn by Krillin, Yamcha, and Gohan as well.
So it's really fresh when he shows up in a very alien design. It's asymmetrical which is cool, a different color palette we haven't seen, looks very Toriyama, and is worn during the great exchange between Trunks and Goku. I'd hardly call it "generic".
These are the same reasons people like the casual jacket Goku, or even farmer Goku.
