so I found this in smash wiki I am assuming it is not an imperforated list of changes but seems to be the major ones anyways.
* Bowser, Kirby, and Yoshi are each heavier.
* Marth, Fox, and Mario are each lighter. This puts Marth below the weight threshold of standing up during Fox's shine.
* Falco's down aerial only spikes for the first half of the animation. The rest sends the opponent slightly up.
* Sheik's up aerial isn't as strong. In addition, it has one less frame of hitbox lag.
* Marth's down aerial is a Meteor smash and in Home Run Contest it sends the sandbag straight down with the bat drops.
* Fox's down and forward smashes are less powerful.
* Fox's up smash weakened, damage dropped from 18% in NTSC to 17% in PAL, knockback dramatically weakened, for example, in PAL-version Peach would die to Fox's Usmash at as high of a % as 83%, whereas in the NTSC version Peach only needs to be at 70% for her to Blast away as a screaming star.
* Yoshi's forward smash is more powerful.
* Peach's dash attack is less powerful.
* Luigi's neutral aerial is less powerful.
* Ganondorf's down aerial inflicts less damage, from 22% in NTSC to 21% in PAL.
* Ganondorf's forward aerial has dramatically decreased in terms of knockback, in PAL his back aerial is more powerful.
* Yoshi's down aerial inflicts less damage, from 44% in NTSC to 36% in PAL.
* Fox's forward aerial has more range on its hitbox.
* DI on Sheik's down throw has been changed so that it can no longer chain throw consistently.
* Fox can tech out of Falco's down throw in PAL.
* Link's spin attack is no longer a semi-spike.
* Bowser's down throw can hit Mr. Game & Watch.
* Link's super jump glitch was removed.
* Samus's extended grapple beam was removed.
* The Ice Climbers glitch was removed.
* Lag and loading times have been reduced.
* The 'Special Movie' was removed.
* In Home-Run Contest mode, the platform is longer and the invisible backwall is a bit farther.
alot of these seem almost random. nerfing yoshis dair? making mario lighter?
it seems like the by far the greatest nerf was done to sheik with the Di on her down throw.
which it has been argued gives low tier a greater chance in tournaments, because as kirbykaze would say, sheik keeps low tiers on a leash.
but I think people are forgetting that marth, falco and peach severely restrain low tiers as well and other than their spikes marth and falco are seem pretty much the same, two characters which I think are played alot more than sheik, and in europe it seems fairly evident that low tiers are not tournament viable.
however japan does have some very good yoshi players.
but I think the main focus here is on sheik, I think that if america were to switch over to pal that sheik would be lucky to break top five in major tournaments. and I wouldn't be surprised if falco's started doing a lot better.