by that standard bf would be better.
edit: but this is the right train of thought
Ok I did some testing, I stood on the bottom floor of the stages and did a shoryuken against DK with no DI the %'s posted are when DK died on that stage
61%-Battlefield, Final Destination, Norfair, Lylat Cruise, Pokemon Stadium 2, Distant Planet, Smashville, Pokemon Stadium 1, Brinstar,
62%-Yoshi's Island, Pictochat
81%- Jungle Japes
Rainbow Cruise- 52% on ship, 52-60% while stage is moving, 55% while on top
Delfino Plaza, while on moving stage 61%, while on ground 58-61% depending on which ground stage it is.
So for early shoryuken and up angled forward smash kills alone, Rainbow criuse is the best.