From: US, central standard time
Actually I consider concessions as major victories.
So, all a player would have to do to avoid a Decisive Defeat is to resign? And the only way a player could gain a Decisive Victory is if his opponent stuck it out to the very bitter end? Why doesn't that seem quite right?
I think that by resigning, a player is acknowledging that the game is going to end in a Decisive Defeat, and it should be recognized as such. A player should never come out ahead by resigning. It is simply a way to avoid enduring a beating.
And as far as this simply "declaring" a game a major or minor victory business goes, if I am not mistaken there are specific conditions for these victories to be awarded, listed in the game for all to see. If players can simply declare a result whatever they want without meeting these conditions, then what meaning do these artificial victory titles have? What is a major or minor victory? Whatever the victor says it is? And of what value would a ranking system based upon these artificial titles be?
I think these issues would probably need to be addressed before you could roll this out.
It's already rolled out. You are free to start one yourself, I wouldn't mind saving my time. This is just a guide to help find suitable opponents. You are free not to participate.
In terms of decisive defeat or not, then perhaps the agreement can be between players that they must resign as a decisive defeat or the player will not accept the resignation. In the grand scheme of things, it only matters a few points in a game and the real separation in ratings will be playing several games.