For all questions, use the official BR stagelist for online play.

1. You're playing a tournament, and your BM is very on point so you aren't using anyone else. You come up against a Marth in tournament.
a. Assuming you strike first and there is a 1-2-1 striking system, how do you think striking will go? Why would each player do what they do?

I would first ban Yoshi's Story. Due to the cramped nature of the stage, Black Mage will die earlier, his on stage game is hampered by the small stage, and overall I believe it to be Black Mage's worst stage in general.

I assume Marth would then ban Dream Land, due to its large stage and blast zone, which allows Black Mage to live longer as well as promote more of the character's long range zoning, effectively giving Black Mage a stronger neutral. He would also ban Nintendo 3DS. While the stage is small, the lack of platforms can allow Black Mage to effectively set up his defensive wall. The stage's blast zones are also much larger than Yoshi's, giving Black Mage a bigger advantage offstage while either edgeguarding or recovering.

This leaves me with the choice between Battlefield and Smashville. Battlefield's platforms allow Marth to breach Black Mage's zoning game much more easier than Smashville's lone platform can offer. Battlefield, due to the shape of the platforms, allows Marth to catch Black Mage's landings a lot easier as well, thanks to his long reaching sword and Black Mage's average air speed, while the Smashville platform allows Black Mage to effectively retreat from a situation at will, giving him more of a stage presence. Therefore, I would decide to ban Battlefield, leaving us to go to Smashville for Game 1 of the set.

b. Analyze the BM-Marth matchup in detail (neutral game, punish game, offstage game, whatever else). Finish with a matchup ratio (60-40 would be unambiguous but small advantage to BM, 30-70 would be very large advantage to Marth)

I honestly find Marth to be Black Mage's toughest matchup, mainly due to Marth's ability to safely pressure Black Mage with his sword. Black Mage will want to try and catch a miss-spaced aerial, or an unsafe approach from Marth while using his best spacing tools (Meteor, Ftilt, Uair) to pressure Marth to approach, in order to get a grab and rack up damage. Marth, due to his incredibly safe poking tools, can find safe and effective ways to break this defensive wall, with his long ranged aerials.

Black Mage can punish Marth well, with his weight and height being great for him to land both combos and juggles. However, Black Mage has to be weary while comboing Marth, due to his quick aerials which can easily lead into a punish. Marth, once he opens Black Mage up, can rack up damage quickly with his aerials, and force Black Mage into a disadvantageous state, letting him possibly take more damage. Marth's tipper moves can easily take an early stock, but if Black Mage can avoid them, he can live to extraordinary percents. Marth can also do the same in return, if he avoids Black Mage's kill moves (Bthrow, Bair, Usmash) and edgeguards.

Black Mage thrives off of edgeguards, and with moves like Meteor, Dair and Fsmash, he can take Marth stocks at extremely early percents. Marth has to resort to making a mix up to avoid Black Mage's guard. Marth however, can edgeguard Black Mage rather well. He can poke through aerial Meteor 1 with his own aerials, and edgeguard Black Mage hard, regardless if he goes for a tipper Bair or Dair while Black Mage is warping, or useing a move such as Fsmash to catch him after Warp. While Marth has to work harder for his edgeguards, Black Mage does not have the mix up game that Marth has on the opposite end.

Overall, I believe that Marth can capitalize on Black Mage's mistakes harder than Black Mage can to him, as well as having an easier time in disadvantage and in neutral. I believe the Matchup to be 65-35 in Marth's Favor.

c. Your opponent lost the first game and is thinking of switching to Samus. Would this be a good idea, from a matchup perspective?

In my opinion, no, due to my belief that Samus loses to Black Mage on a score of 60-40.
Black Mage can play around Samus much better and easier than against Marth.

2. I propose the following stagelist while we're deliberating on an update to the current BR stagelist for offline play.

Neutral:
Battlefield
Castle Siege
Final Destination/Nintendo 3DS
Smashville
Pokemon Stadium 3

Counterpick:
Yoshi's Story
Tower of Salvation
Dreamland
Dracula's Castle

a. I'm guessing you support the removal of Sky Sanctuary Zone from this list. Why?

I honestly find Sky Sanctuary Zone as an extreme counterpick stage, considerable to the likes of Mute City and Delfino Plaza from Melee and Smash 4 respectively. The stage has a smaller than average ceiling, and with a stage list already featuring plenty of low ceiling stages, (Pokemon Stadium 3, Yoshi's Story, Mirror Chamber) having a fourth stage with similar blast zones seems too much for an overall stage list. I find the extremely small offstage area to be too much of an issue for characters with poor options offstage, regardless if they have a great recovery or not. The uneven platform at the bottom of the stage is also an issue, hampering characters with projectiles while travelling up it, while making those same projectiles even stronger while travelling down.

Overall, I find the main reason for the banning of this stage to be its overall campy and extremely defensive nature, and its ability to make some matchups extremely lopsided, especially towards top and high tier characters. Sitting underneath the platform while using a move that forces approaches (Lloyd's Grave Blade, Donkey Kong's Giant Punch, Zelda's Din's Fire, etc) can result in opponents having no choice but to approach. Due to their position under the platform, and the risk of challenging strong anti air combo starters (Lloyd's, Donkey Kong's and Marth's Utilts, for example), characters such as Sora, Sheik, Captain Falcon and Tails are forced to approach in a linear and usually unsafe way. This extremely strong camping spot, strengthened by just how long the top platforms are, as well as the stage's small blast zones, can make neutral a nightmare for characters who dont possess quick anti camping moves (Fox's Lasers and Chibi-Robo's Chibi-Blaster are good examples). The stage honestly just sways too many matchups for characters that already do extremely well in normal situations.

b. Is this list better than the official offline BR one? Why?

I find the position of Castle Siege over Yoshi's Story as a neutral stage to be questionable, as I would of personally removed it for Dream Land The removal of Sky Sanctuary Zone and Mirror Chamber allows some low tier characters to compete better. I feel that the position of two large stages (Dream Land and Dracula's Castle) as both counterpicks to be questionable, especially without more stages to make it not as big of a problem. I overall believe that it is slightly better, but a knowledge of how many stage bans one gets before a counterpick on both lists might sway my position.

This is a bit more informal of a followup, but I'm interested in hearing you elaborate more on this. Opinions on this are pretty divided, so I'm just interested in what arguments you have.

3. Is part of the role of a stagelist to balance the game (i.e., keeping stages that top-tiers struggle on, removing stages that top-tiers are extremely good on)? For example, in the history of the Brawl metagame some stages were banned (Rainbow Cruise) for not being amazing stages to fight on perhaps, but more importantly because Meta Knight was extremely good on those stages and the main concern of the Backroom at that point in time was preventing MK from becoming better than he already was. Similar examples in other games abound. Do you agree with this mindset? Why?