haha, more test games needed. But yes, when chances to get 2 checkmates myself go towards zero, there is no more excitement because there isn't even a point in trying to get 2nd or 3rd.
Points don't really matter either anymore. it's all about getting 2 kings.
Try it folks. what do you think?
What is excessive teaming up? It is when 2 players in Solo (FFA) play like a team during the whole game (or at least while there are 3 or 4 players), trust one another, hang pieces, attack other players together and often also gift points to their partner at the end of that game.
It is not just short-term cooperation when there is a risk (possibility) that "temporary partner" may "betray" at some point. Natural Short-term Cooperation is what we want to keep in Solo (FFA). Excessive Teaming Up is what we want to eliminate.
Why do we want to eliminate it?
1) An opinion and etiquette of our community is: Teams (team players) should play in Teams mode, while FFA (Solo Play) is for individuals which may cooperate naturally, but should not form teams.
2) If 2 players form a team in Solo (FFA) they become a super-player and easily kick 2 other players from the game. It is the easiest way to win currently. As a result, the game looks as "solved" and fun disappears. This is not what we want. We don't want a simple teaming up strategy be the way to win in Solo (FFA).
That is why we actively look for an anti-teaming solution.
We want fun and cooperation to stay, but don't want blatant and straightforward teaming strategy to be the best.
A 4PC Solo (FFA) game consists of 3 stages:
1) 4 players on the board.
2) 3 players.
3) 2 players.
1) At the beginning (4 players) there is a balance. And there is no teaming yet. Even if Red and Yellow unite to kick Blue, they are not a team yet. They cooperate, that is fine. So, there is no need to implement anti-teaming Rules changes to "4 Players" stage. We can add some changes, but it is not a must.
2) Once 1 player is checkmated/resigned, "3 Players" stage starts. At this stage there is a so called "sandwich": 2 opposite players and 1 between them. "Sandwich Bread" players objectively have better position due to the board geometry. This is an imbalance. In addition, if the bread guys are in a "team", the sandwiched player has no chances to be the 1st or 2nd.
This stage is the moment when we may want to "turn on" some rule to balance the game. (Because we cannot change the board geometry.)
And this is also the moment when teaming up discloses itself. So, we want anti-teaming rule(s) to start working here. Because even if we balance the game somehow to make the sandwich homogeneous, (pre-arranged, over trusting) teamers will continue attacking the sandwiched player together.
At this stage some rule like "sandwiched player gets double points for piece captures" looks reasonable. Maybe not double, maybe 1.5, I don't know yet. Here I reason about the principles, conditions and theoretical ways, it is a draft.
One more condition we want to keep in mind at "3 Players" stage is: Any player should have a hope/chance to win during a game, for as long as it is possible. Otherwise the game may be spoiled quickly by a kamikaze.
3) Once the "2 Players" stage starts, we see new tasks:
a) We don't want players to gift/feed too many points one to another.
b) If 2 last players played like a team in this game, we want only 1 of them to win. Another 1 must lose rating points. This should make teaming up strategy not optimal.
At this stage we may leave or remove the balancing rule(s) from "3 Players" stage. Or they may be removed as non-applicable automatically, because there is no sandwiched player any more 
3b) may be fixed by "1 winner 3 losers" rule (or conditional rule) or by reducing points of 1 (or 2) last players under some conditions, so one of them become the 3rd.
We have lots of ideas now. The task is to keep all the requirements in mind, and also not remove fun and not make the Rules too complex. I think it is possible.
During testing of some rules changes we realized that 1 more requirement should be met: Any player should have a hope/chance to win during a game, for as long as it is possible.
If some player loses his hope, he may start making emotional moves: self-destructing, kamikaze, trolling, etc. He spoils that game, but doesn't break any rules. Of course, a non-infantile person won't do that. But ...