I assume that your point is that the player playing black moves all pieces, also playing white's turn. I also assume that white did not build an edge fort (otherwise it is an identified win for white, or maybe a draw but still well identified). Then either the king is in a draw fort, or the king can be captured by 4 attackers. If the king is in a draw fort, the player playing black can destroy the fort on white's turn and then the king can be captured by 4 attackers. In all cases, it seems to me that a sufficient (and obviously necessary) condition for black to win is to have 4 or more pawns, and your rule reduces to "black will then win, except if he has less than 4 pawns, in which case it is a draw". This looks more like an exception than a rule ^^ It does not help to solve the repetition issues.
Actually with the edge fort set as winning condition, what's the problem with stating that any repetition is forbidden for white? The only case I can think of were I would like to justify a draw for white is when white has a central fort and black too few pieces to enclose it. It looks like the king is quite safe in this case (not "starving"). This may even enrich white's possibilities with a reborn of the central fort! White's strategy would more or less looks like:
1/ Try to reach a corner!
2/ If all corners are closed, try to build an edge fort!
3/ If it seems not possible, use all your tactical machinery to decrease the number of attackers and build a big central fort in the same time.
But again it would be very difficult for white and probably impossible at high level... The minimal number of pawns required to build a central fort is 8, so white can only afford to lose 4 pawns. And to enclose it black needs only 12 pawns. So white has to exchange 4 defenders against 12 attackers. Seems tough!
1. White wins by reaching a safe position where it is not possible to capture the king nor to enclose all defenders with only black moves (this last precision in order to get rid of diagram 8b : if black contests white's claim for the win, he can move his pieces as he wants and try to capture or enclose)
2. Black wins by preventing white from winning.
3. Stalemate = loss.
4. White must break any repetition cycle, except if he reached a winning position before the repetition.
1. White wins if:
- king in a corner
- edge fort
Black wins if:
- he captures the king or encloses all defenders
- he forces white into a repetition cycle.
- the board position is repeated several times.
- all defenders have been captured and the king cannot escape
- the corners are closed and only 3 defenders remain
- the corners and edges are closed and white has too few pieces to shieldwall capture
About the closure of corners and edges, I think it is an important point. When playing black, it is quite boring when the corners are closed and the edges sealed such that the only thing to do is to push everything towards the center. The win is obvious in these cases but still under the current rules black has to play it. In pratice black could claim his victory, and again the board is frozen and white can try to show how to build an edge fort or escape, moving only the defenders.
In any case, I think that this formulation is elegant and functional, very close to Copenhagen while solving its issues about repetition. However I still have the intuition that if the attacker force is "very destroyed", it should be a draw even if the remaining attackers can prevent white from winning. For instance if there are only 3 defenders remaining, each blocking a corner, against the king alone, and everybody is desperatly running from one edge to the other... But I don't manage to find a proper definition of "very destroyed".
EDIT : I got an idea. Actually my concern is that this rule of white losing if he doesn't win encourages black to play very safe, and almost not play at all when in a good position (not risking to lose on a mistake)! What is white can "call for a draw" at any time? In this case, either black accepts the draw, recognizing he cannot prove that white cannot win, or he continues playing without the threat of losing in order to either capture, enclose, or put white into a repetition cycle. If then white manages to win, it is a draw. If black captures or encloses or white repeats, black wins.
I'm thinking for instance of a situation where black can close some corners and seal edges easily, but has too few pieces to do both at the same time. He needs to open the corners to bring pieces in the center, giving a possibility for white to escape. If a non win if a loss for white, black has no interest in risking this.
EDIT 2 : On a terminology note, I would put the stalemate, move repetition and board repetition in the same loss condition for white :
3. Starving : if white cannot make progress towards the win, white loses.
EDIT 3 : Other idea: in case of repetition, all pieces in the repetition cycle are removed (because starved to death), and then the attackers play. The king can be removed this way if he is in the repetition cycle, in what case the attackers win.
As they often involve the king, repetitions would then often mean the threat of a loss for white, which reduces to our previous idea. However when they do not involve the king, they could become a nice tactical tool to exchange pieces (e.g. to simplify the position before endgame).