Can they teleport now? Going past me to the other platform when I grab the ledge requires going past me. I just hit them when they try that nonsense. Remember both of these stages are very linear. Unless the other guy goes really high or really low, generally your only option to get to the other side is to go through them. If they are playing so passively you can easily just jump past them, that's really their own fault.
To go through character by character:
MK has so many answers I don't think it's worth explaining.
I counter Mk's answers, with MK being the one on the outer platform. =p
Snake can murder your shield with explosives. If you can consistently powershield properly cooked grenades and smart nikitas, I'd be impressed. He can also jump up high and put a C4 down on the platform and then mix in the detonation of it with his other explosive pressure. Remember you have time as well so if you want to pre-emptively make a side platform a pain to use, feel free to put a down smash mine on it.
Though Snake is capable of grenade cooking, it takes time. 3-4 seconds for each grenade that he's going to lob in the direction of his opponent. The point of holding control of the outer platform is to remove the commodity of
time. Grenades do not do a lot of shield damage. By the time a second grenade would be throw, the shield would be almost at full.
If a Snake is attempting to Cypher to drop a Mine... then he's being a moron. It's incredibly telegraphed, and allows his opponent to simply go to the other side of the stage, all while Snake takes the 10 seconds to do it. Let's not forget the position that Snake is putting himself in to drop a mine. As a character without adequate options on landing, he's just given his opponent an opportunity to increase the damage lead that he already has.
Wario doesn't mind jumping at you and can use his aerial mobility to easily retreat. I don't think Wario's game plan really changes much at all.
Actually, it does. Considering the one thing Wario doesn't want you to do is grab him in most match ups, he would have to be overtly careful in approaching this situation. Wario is at his strongest ascending, rather than descending with his aerials. If a zoning based character was on the platform, what would Wario be able to do, in all honesty? His best option is to go in with an aerial and then auto-cancel it, but this can be beaten by pivot grab, and if the individual on the edge has a half decent aerial/oos option, they can just knock him back off the disjointed platform.
Diddy Kong can use peanuts to put you into a powershielding test if he wants, or he could throw a banana down onto the edge of the platform and use it to cover his approach (being ready to smack you with an aerial if you go for it yourself). Landing behind his banana is the idea for him.
Banana could be grabbed with a jab by most characters with ease or air dodging into it, or they use the fact that one banana is now on the stage to retreat to the center of the level. Diddy would then want to go grab his other banana, and the process continues assuming adequate mobility for the character that is camping. As a character though, it's hard to keep Diddy from gaining control of an area when he wants it.
Marth can just retreating fair shields repeatedly pretty much safely. Fair the shield with your tipper, pull back, and grab the far ledge or land on the central platform. Repeat a lot. If they back up far enough to make it difficult, land on the ground on the center stage side of the platform and enjoy your commanding position.
Another character with good options against a shield. Marth is able to use his disjointed, good aerials to gain control, as long as his opponent doesn't have better options, or a projectile to slow him down.
Pikachu can rain Thunder and Thunder Jolts on you until he decides to QAC onto the platform really fast and do his usual business. Pikachu can make really smart use of those ledges and the center platform to stay unpredictable while going for the far platform with his unique mobility.
Yet another character that wouldn't have much of an issue. Conversely, another character that would be amazing to be on the actual platform vs another character.
Mr. Game & Watch I covered earlier. In addition to what I said, he can use his fair kinda like Marth uses his. G&W is pretty strong in these situations.
Agreed, unless his opponent has better disjoints than him. Such as Marth or MK.
Toon Link can easily use his projectiles to at least give him an opening to land on the platform. He has three of them and can use them in unison in smart ways. He also can use zair safely to land.
Zair isn't safe on shield. Toon Link has enough projectiles to where he wouldn't have to approach onto the platform. It's always strange playing against a Toon Link, since he only needs to approach to kill really. Bombs are relatively annoying to power-shield consistently and so they have the chance to shield push you off of the platform.
Really, I don't see any need to go beyond here in your points, since most situations are beat out by a matter of WHO is on the platform, and WHY they are there. People go to the platform to waste time, so that they can mount damage against characters that are forced to approach them due to their percent lead. Marth isn't going to wrestle control of the platform from MK, and Game and Watch isn't going to get Marth off it either.
It's a situation that gives entirely too much control of the match to whoever has the lead and the right options to stay on those platforms. [Why would they have Cp'ed there anyways, if they didn't?] Even still, with the proper options, due to the relative size of the level and the ease of navigation players constantly do a cat and mouse battle as they run around the stage. When I look at stages, I often ask myself:
"Would I want someone to view this as the first tournament match they've ever seen?"
The answer for Japes is pretty easy. It's a boring stage that encourages players to
camp time-out due to the composition of the level. Being on the platform isn't an unbeatable tactic, but rather one that will tilt the percents in the favor of the player that is already in the lead, and waste time. If a player is mixing up between a decent aerial/projectile and shielding, it is incredibly hard to get them off the platform without putting yourself into a position that won't allow them to just go to the other platform. My personal bias in all of this, is that I have never seen a match that didn't almost run the timer on this stage.
As mentioned before, I do believe this would make for an amazing Team's stage. We've discussed doing so in Louisiana before, but our team's scene isn't really alive due to an unbalance in player skill. So the conversation more or less stagnated. I would be perfectly OKAY with the addition of more stages into the conversation for Teams, but Japes stands as a horrible stage for singles.
The main character that would look to Japes as a CP would be Falco, and that would simply open up FD as a counter-pick for him, instead of being banned. The more stages that are included at a tournament, the less intellectual and important the ban that a player has. Stage diversity is important, but we should be careful about the inclusion of stages that leave a player in a position of.... "Well I can ban one ganky stage, but my opponent will still be able to take me to two more."
Ps: On the note about Rainbow cruise, I believe that as a stage it doesn't belong in tournament play. It is completely opposed to the normal way that Brawl is played in a competitive environment, and it tends to be a last ditch effort counter-pick by players that are outclassed in a conventional sense of a match up. I can't tell you how many times I've witnessed lower-level players pick it against someone else in hopes to have the stage beat their opponent for them. As mentioned, it's the only stage that continually moves during the match. There's a noted lack of ledges to grab on the stage as well. It's a bad stage for competitive play, but it'll remain for the same reasons MK won't be banned anytime soon.
Then again, unlike most TO's I didn't automatically switch to anything that MLG is doing. Louisiana as a state came to terms with what stages we were going to use, and have kept to that by and large.