As I understand it, the point of the XP system is to introduce players to the game gradually. As they get better, they get more XP, and then can use that XP to unlock better units. It's a novel concept that should work great.
However, some players can catch on more quickly than other, and more importantly, many players were here long before XP system was put in place. I've used every unit in the game successfully, but suddenly I'm finding myself locked out of many unit choices because I don't have the XP to buy them. I just found myself in a sea battle where I desperately needed a reef for mobile anti purposes, and found myself unable to build it.
What if scaling was applied to the XP rate gain that took Elo into account? If a player has higher Elo, they're obviously learning quickly and should be allowed to have more advanced units.
Some users have already argued that the opposite should be used, so that lower Elo players gain XP faster. I must remind these players that XP isn't about how good you are, the entire system is used to hold new players back from advanced units until they can learn how to use them properly. For example, I've seen many green players try and rush Singularity reactor at start, or even a Starlight! The current XP system works to prohibit this, and hopefully by the time those players have the XP required to buy Starlight, they will be smart enough to use properly. Since Elo is a measure of skill, higher Elo means that the player is progressing faster, and therefor deserves the unlocks faster.
In conclusion, since higher Elo players are performing at an advanced rate, they deserve to unlock advanced units fast. That, and I'm also pissed that the same units I've been using for a year are suddenly unavailable.