This is a pretty cool idea; it actually inspired me to make a somewhat different version of it. I suppose I should post what I have. This was really fun to design; I think the main distinction between mine and yours is that mine is more complicated which makes the actual board game more important. I'm not trying to steal the show; I just kinda got carried away, and after all this work I pretty much have to post it.
The main change in my version is that players are no longer represented by pieces, characters are. Each crew has 16 pieces (with presumably 4-8 players, uneven numbers per side don't matter at all as long as each crew has at least 3 players). Each piece represents a character with lower tier characters having more favorable movement rules in general. Instead of just having n tile movement, I devised a system of movement rules that makes the team more diverse. I'll post a picture of the board for brawl so people can think about where they are moving across.
The next big thing is the piece movement rules. I slightly changed the current tier list around to make the piece balance work out a bit better. Each team gets to select which characters they use for each type of piece (no two of the same character). Unless noted, pieces are unable to "jump" other pieces.
Movement rules
1 in cardinal direction (1 total) - S
Meta Knight, Snake
1 in any of 8 directions (3 total) - A
Falco, Mr. Game & Watch, King Dedede, Marth, Diddy Kong
2 in cardinal direction at max, can't change direction after moving first square (2 total) - B
Wario, R.O.B., Lucario, Olimar
2 diagonal at max, can change direction after moving first square (2 total) - C
Pikachu, Kirby, Donkey Kong, Ice Climbers
chess "knight" with ability to move 2 or 3 squares before changing direction (can jump pieces) (2 total) - D
Samus/Zero Suit Samus, Toon Link, Pit, Peach, Wolf
chess "bishop" (limit 5 squares) (3 total) - E
Luigi, Zelda/Sheik, Bowser, Fox, Ike, Ness, Sonic
chess "rook" (limit 5 squares) (2 total) - F
Mario, Lucas, Pokemon Trainer, Yoshi, Link
chess "queen" (limit 5 squares) (1 total) - G
Jigglypuff, Ganondorf, Captain Falcon
The top two and bottom two rows are the "starting zones". Pieces are arranged on the bottom as such.
BACASCAB
FDEEGEDF
Then the top is a mirror version of that (the S characters oppose each other).
The bottom player moves first (side is determined before the game by coin flip), and on each player's turn he must move three different pieces (no more, no less). If the player has 5 or more pieces in either starting zone (his own or his enemy's) at the start of his turn, he must dedicate at least two of his moves to removing pieces from the starting zones if possible. At the end of his movement, if the player has any of his own pieces directly adjacent (4 cardinal directions) to any enemy pieces, he selects one of those pieces and an adjacent enemy. If he has any pieces either adjacent to the enemy's selected piece or to both his selected piece and an enemy non-selected piece, he selects one piece among them (if not, piece selection ends and it goes to a 1v1). If the enemy has any pieces adjacent to the attacking player's selected pieces, he selects one of them. If not, the enemy may select a piece adjacent to his own selected piece (if the enemy selects a piece at either step, a 2v2 begins). If the enemy was unable to select a second piece and the attacking player has more pieces adjacent to the enemy's selected piece, he may select a third of them, and at that point a 2v1 or a 3v1 begins. The attacking player selects any stage on which he has a piece that will be involved in the battle.
The people who battle in each crew will be decided based on a queue. Before the game, each crew has to order itself in a sequence of their choosing. However many players are needed for a battle will be taken from the top of the queue, and they may select characters from their team freely. After a battle, participating players are shuffled to the bottom of the queue. Example:
We have a 2v2. Team A selected Mario and Pit while team B selected R.O.B. and Captain Falcon. The players in the top and second highest slots of the queue from each team play, and they agree among themselves who has which character. After the battle, the queue is in the order 34512 for each team regardless of character selections.
After the battle, every involved piece moves back 4 squares toward its own safe zone (they can move through each other). If a non-involved piece or the edge of the board is in the way, that piece will use one square of this movement to move horizontally toward the center of the board (if the piece is in the middle two columns and can't move back, it just stops moving). If multiple pieces end up on top of each other by this, the attacking player moves any offending pieces to the nearest available squares at his discretion. Then, if the attacking player has a piece not involved in the last battle adjacent to an enemy piece not involved in the last battle, he may choose to have a second battle (he isn't forced to, and pieces used in the last battle are allowed to be called in as teammates). That ends the turn; crews alternate until one crew runs out of stock.
Battles always last 3 minutes, and each crew is worth 6 stock per member of whatever the biggest team is. Friendly fire is on, and set the stock per match to 99 or something so no one will ever run out. Record the percentages at the end of each match and add them together as well. For every total 400% your crew accumulates in this way, your crew loses a stock.
I also made a melee version. Replace 400% with 350% and use the following board and character set.
Melee version
1 in cardinal direction (1 total) - S
Sheik, Marth
1 in any of 8 directions (3 total) - A
Fox, Falco, Peach, Captain Falcon, Jigglypuff
2 in cardinal direction at max, can't change direction (2 total) - B
Ice Climbers, Samus, Dr. Mario, Ganondorf
2 diagonal at max, can change direction (2 total) - C
Luigi, Donkey Kong, Mario, Link
chess "knight" with ability to move 2 or 3 squares before changing direction (can jump pieces) (2 total) - D
Pikachu, Young Link, Roy
chess "bishop" (limit 5 squares) (3 total) - E
Zelda, Mr. Game & Watch, Ness, Yoshi
chess "rook" (limit 5 squares) (2 total) - F
Bowser, Mewtwo, Kirby
chess "queen" (limit 5 squares) (1 total) - G
Pichu
