Ok, so I tried to make sense out of the first sentence, but it was really hard so sorry for any mistakes, the english language is not my mother tongue. I believe you're saying something along the lines of "If they aren't limiting configuration options than why does EarthGrab only have an executor left?" And I think that means they removed the EarthGrab yourself feature? (Not sure if they did, I haven't played in a long time).
Note that revamping an entire move and limiting a feature's config options are completely different. EarthGrab was revamped to be a move to capture an enemy or target, and not for personal defence. They might have done such things because they thought it was "OP", or unrealistic, or anything like that. They are simply sticking to the avatar universe like this, not trying to control other servers using this plugin. If I remember correctly
@Mist's goal was to make this plugin as customizable as possible, and that includes allowing server owners to go for a full-on RPG server.
I'm also not so sure what you're trying to achieve with your arguments. Mist has indeed said that he doesn't think a leveling system is a good idea, but does that single statement mean he and the team can't change that decision? Things that happened and have been said in the past should not hold back further development of the plugin, let alone mere statements. And let's above all not forget that bending is not only about fighting. I think this RPG aspect could add a very nice aspect to training, teaching others, and roleplaying.
For the leveling system being OP for a new player vs an old player: How is this solved in games such as Guild Wars 2? The closer you come to the spawn, the lower the "level cap" gets. This could be implemented in the RPG plugin but as well via other plugins, so you really shouldn't worry about it too much. A good server has thought about that and covered that problem.
This plugin isn't a "Do X move Y amount of times to unlock Z". It's much more "abstract" and "open" than that. From what I understand, it allows server owners to "connect" it with other plugins, that will decide what the player has to do in order to receive more skill tree points. I think others shouldn't be too closed minded about this concept.
TL;DR: Go read the post, there is no TL;DR.