Problems with MotS will always be there until developers remove them, and i don't think that's gonna happen.
In argentinian top level, there is no "no mots pact", BUT there is some kind of ethic code between us, and we try to win matches with our own strenght, all people know that i won't play mots against them in league matches, so they don't play mots against me, still this season gave me a few surprises, there was a match key to the 3rd/4th spot and one team played mots in the second round, nobody saw that coming beceause that match was between 2 "old school teams", and another match that really surprised me was a cup match, between 2 teams that never had a problem between them (in fact, the team that received the mots once helped the other to lift a ban!!!!), i must say that those 2 matches caught me completely off guarded.
Relegation war and mots? That's a carnage....
But if i have to be honest i don't think badly about them, i blame the system, not the user itself.... The temptation always be there, people will eventually fall, were made of bone and flesh after all
My point is, i'm not sure that "full league pacts" can be done, i think they would be the perfect thing, but i don't think it can last forever, people eventually falls into the temptation, and with time, that will do a huge damage to the game itself, because communities are the thing that keeps this game alive, and they will die, little by little.