The more I play this MU the more I think it's almost unwinnable in a set with the current Unity ruleset. I play against 4GOD's D3 where he is definitely probably top 3 best D3s right now AND he actually knows the MU... I haven't been 3-stocked in a tournament match in a long time. I wasn't frustrated or playing bad at all. Hell, I don't even get 2-stocked by my regions notable players like Reflex, Kismet, and BigLou usually.
All I'm saying is in the current Unity... if they're smart, they ban Smashville, Battlefield, and Lylat which leaves us with Yoshi's, Castle Siege, FD, and PS1.
I personally detest Yoshi's... not sure about you guys. I can't utilize the middle platform as well as I need too and it severely hampers my air game when he just camps under it all game. I experimented with this last tourney vs 4GOD and got 3-stock on it. Did much better on PS1 two tourneys ago (TO, last stock, lost by 20%, could of won if I had more time... sigh).
Castle Siege's 1st transformation layout sucks imo. 2 platforms to hide under and each segment slopes up or down so you have to approach at an angle which isn't ideal in most situations. 2nd transformation is the best for FIGHTING imo... except the walk-off where one mistake equals death which usually isn't worth it. Smart D3s won't chase you around the platforms obv. They'll just camp you back. And the 3rd transformation is FD that slants, half of the time worse imo.
Final Destination... well isn't the worse imo. You need the platforms to camp if you're going for the TO or just playing safe but at least FD is big and has a lot of air space to float in. Still, no platforms? No thanks.
And last brings me to PS1. One of Wario's best stages imo. The beginning and inbetween transformations is FD with small platforms... beautiful large air space to camp in and small platforms that don't hamper your air to ground game and give you places to escape to at the same time. Add in the fact the transformations all promote camping which helps both charge your waft and TOs... it's probably the best you're going to get for first game imo. The only problem is one mistake at a bad time could lead to a wall infinite and death but hey, we're Wario...
If you win first game, 2nd game is their CP. This is a preference imo but good bans are the classic FD or Delfino. Annoying stages they might like are Halberd, Delfino, FD, or Castle Siege. I would assume most would try for Delfino or Halberd if you ban FD. I personally think Delfino is the best ban since I personally find every transformation to be severely not in our favor but the between transformations are nice for us. I rather air camp on FD and bike away non-stop instead of making one mistake and losing a stock on Delfino (especially that lovely U plaza transformation... *sigh*). You can mitigate CG damage by positioning yourself on the ledge side of D3 too.
If you lose 2nd game on one of their horrible CPs.... you get a CP. Most D3s will ban Brinstar or Rainbow. Some may do Frigate but I doubt it. I personally think the best CP goes Brinstar > Frigate > RC. Brinstar for obvious reasons... D3 dies off the side faster than most chars (he has one of worse drift speeds in the game, so no horizontal MC. Just massive vertical MC since he's top 3 heaviest and THE fastest faller in the game) and the small area with conveniently located platforms helps us put up a fight without taking much damage from CGs. Frigate because our recovery is amazing and the first transformation is great for us, especially edge guarding D3. 2nd transformation isn't as ideal but controlling the center of the stage really helps. I know some probably like RC more but imo the design of the stage is only really good for TO strategies which isn't a bad idea at all. RC helps you position yourself under D3 where you can the most damage while giving you able area to run away to. The only problem is the top area and the boat, one mistake can lead to a loss of a stock or other stupid things. Actually, now that I typed it out, RC is probably better than Frigate especially if you run a TO Strat which you should do.
This is my general take on the MU. I know it very well because 4GOD was my primary training partner for when I was learning Wario. It's a lot about positioning yourself to what the D3 is doing. If he's SH Aerialing... You can FH DJ and do arcing Dairs to punish most aerials. If he FHs Aerials, you can run under and do SH aerials or punish his landing. Poking with Fair is decent on the ground (be care of pivot grab) and our running grab beats his pivot grab. We can combo him at low percents easy and our Uair is still safe on shield if done right. So using appropriate amount of Uair pressure and Bites, can give you some safe damage. But use falling Bite sparingly... D3 rolling = free grab. He can standing pivot grab bite too btw. FH Bite vs D3 works well imo since once you get him up there, his horrible drift speed traps in in the bite's hitbox with no where to go.
The real damage comes from edge guarding D3. If he goes low, don't be afraid to go for footstool. If he UpBs, you can double footstool off the animation and rise up with him and hit him with the aerial of your choice. If he aerials, you can footstool off it and grab the ledge and he loses height forcing him to UpB or give you a potential Nair off ledge. Bite is amazing if he recovers with low amount of jumps and grabbing the UpB to repeated pummel works infinitely if he has NO jumps. If he grabs the ledge and tries to Bair off it, our Ftilt will trade when spaced right. Dtilt > mix up like Fair can also work w/o trading but it's hard to space it right imo. If he recovers high, rising Nair is the best way to send him out.
Never be at an equal aerial level as D3. You will lose to Bair or Fair (unless you beat the speed on Fair) every single time. Always rise or come down on a D3 by a good margin if he's in the air. You can also SDI his Dair and Uair to an aerial of your choice if you practice.
Regardless of what I've said, if the D3 understands all that I've said here... the MU is horrible. I know it's stage dependent but overall I personally feel it's close to -3 (at least -2.5 if it existed). That's my take at least. I'd love to hear what others have to say about it. Especially people who've actually faced GOOD D3s (which are rare now days imo). Coney, Zekey, Atomsk, and 4GOD are the only ones off the top of my head.
Also, not sure why I typed all this up in an out dated MU thread but I was just bored and frustrated about this MU so figured I'd share my 2 cents. Wish we had MU discussions going on like in the old days.