I haven't seen a lot to suggest that (maybe you guys need to upload more G&W v ICs matches!), what with G&W's mobility and ability to split them up. Planking helps too, and platform camping if you can get something like YI/Lylat/BF. Their Uair isn't so bad, since they go to engage you and they can't grab while they're in the air.
I mean, I might be ultimately wrong, but I don't really think they're as hard as MK. Doesn't Zac do just fine vs Hylian? They seem to play each other a lot, too.
Yoshi's island is the 2nd worst neutral out of the beginning 5 neutrals. It goes fd-yi-bf-sv-lylat. Their uair is indeed bad for us, because it beats dair and they can just keep safely poking with uair to rack up damage. Ice block camping > planking. I have to come up with ******** theory-crafting to win this matchup most of the time =/.
I've kept this to myself, Zac, Penta, and Today, but I'll post about it I guess. 4 gimmicks/tips that allow g&w to be able to win the matchup in tourney:
1. Dtilting on platforms, especially the SV platform, is very good and hard for the ICs to get in. You can go for fairs once the platform is on either side.
2. Here's a platform. G&W is X.
______X__
You want to stand about there, and shield. Bait the uair. Here, you will fall off the platform once your shield gets pushed off, where you can buffer a uair which connects before they land, thus shooting them up, which leads to juggling/separation. MAKE SURE YOU MASTER THIS SO YOU DON'T FALL ONTO THE GROUND! If you do this, it could lead to being tech chased, which might result in you dying
.
3. Bucket has crazy range, so you can actually platform camp if they're blizzarding, bucket it, and use it to do one of two things:
-bucket through their desynch blizzard wall to separate them (the #1 priority in this matchup is to separate them and take advantage of Nana).
-use it for killing.
4. Don't let them land! Keep uairing and nairing. Don't let them air dodge through or around you. You want to juggle nana with nairs while you keep popo away. SAVE FAIR (or bucket) TO KILL NANA! It makes life a lot easier. Also don't sleep on popo, that matchup is evenish.
edit: forgot this last part. When separated, Nana can has linear DI to popo. She can only run to popo or occasionally jump (*NOT AIR DODGE*). If you hit Popo away far enough, you can actually charge a smash and she'll run right into it. You can also nair and juggle the **** out of her.
Also: When you hit nana away offstage, Popo will likely try to save her. GRAB POPO!!! Same goes for when Popo's offstage. If you have one climber grabbed, the other one will most likely be unable to recover.