Ok, I see your reasoning. But I Think That Amethyst was possibly going to go to white diamond, here is why.

1. Her clothes coloring all have to do with the color white, like how jasper and Peridot go with the color yellow, and Lapis goes with the color blue well.
2. The diamonds are all symbols for actions on the battlefield. You probably thinking im cra cra, but im not. If we can assume Rose was a quartz soilder that had served for pink diamond, and rose can heal, and often when you think of the color for healing the color pink comes to mind. So, Pink Diamond was the healer on the battlefield. Yellow diamond is reffered to 'the great decision maker on homeworld' so we can assume that she makes all the battle decisions on homeworld. On the mural with White diamond and Rose fighting, white diamond was the only one attacking, all the other diamonds were doing other biz. And when we seen Blue diamond in 'The Answer' we see her not really fight in the scene, only really the rubies fought back it felt like, and the rubies on their uniforms did not serve anyone, only sapphire, who is not a diamond. You see where I am going with this? On the battlefield you must Heal for you may keep going. You also must make great decisions that could cost you your life, but you have to fight back, and Protect yourself.
3. Peridot reffered to Amethysts as 'a strong quartz gems' meaning that she was the best at attack or one of the best attackers on homeworld. Or her type of gem was. And we have seen within the show the amethyst we have can almost beat garnet without any powers while garnet had used her gauntlets. And how strong jasper was when she fought garnet. See if amethyst was a normal quartz soilder, she would more than likely to be stronger than jasper.

so yeah, I talk too much :P