New stage list isn't going to make Jiggs suddenly worse.
Certainly not.
It wouldn't stop Mango either; he's got good secondaries.
What it
does do is lower the bar.
Let's assume that Mango is a smash god. He will win 98% of the time on his counterpick (he has a good CP) and 98% of the time on the neutral stage (we're assuming they're all good for him and he's better than his opponent).
The only advantage you're going to get is on your own CP. If you take Mango's Jiggs to Pokefloats and laser camp the hell out of him, you abuse Jigglypuff's natural weakness: poor mobility! You can do the same thing on corneria and mess her up since Jiggs is so light.
Now if you lower the stage list options to be primarily the
same gameplay on every stage and only have a few slight variations (die 10% faster vertically, 10% slower horizontally, more plats, less plats, etc., etc.), what you're going to find is that whoever benefits from the stage list the most will win.
The example above gives a hypothetical 2% chance to beat mango on the starter or his CP; the odds of doing this twice are astronomically low. If you're able to do it once, you need to be able to win on your CP. If your CP is just your favorite version of stages that Mango also likes, you might as well make it a best of 1.
There are very few anti-Jiggs stages left in Melee. You've lowered the stage list so much that if something works on one stage, it works on almost EVERY stage. This is unheard of in smash, and really lowers the variation in gameplay. That's great for Jiggs, because she's very straightforward and can't adapt nearly as well as, say, Fox.
Create a stagelist that prefers multiple kinds of strengths, get multiple characters showing their strengths. Create a stagelist that prefers only a linear, single type of strength, you'll see the same style of play.
Lol, let me guess, next I get to hear about why items are legit.
Items are not legit. There are specific spawn zones, but where they spawn in relation to them and why they spawn are random and uncontrollable. To make matters worse (and this was the final straw back when items were finally universally banned), some of the capsules
explode. You can't turn them off, so items are a no-go. Random exploding of your character is bad.
