The whole dexterity things smells like PC backtracking to me. If you throw dexterity on top of that it is unbalanced.
So regarding the Siuan/Leanne situation. Are you actually proposing that Leane was referring to the numerical strength level she is now at, rather than to the amount of Power she can now channel?
In other words, when she says she is less than half as "strong" as she was before, are you trying to suggest she was not referring to absolute strength, but instead to her numerical position on a scale which only includes Aes Sedai?
It is important that you clarify this, because if this is seriously your contention then it is a position that is easily refuted. But first I want to clarify if that is indeed your argument.
Not the actual numbers of these levels. I don't think the Aes Sedai have actual numbers for these levels, but they are the people most acutely aware of them.
Now, I'm not saying the sentence cannot be read the way you read it. I'm saying, however, that since extra-textual sources (RJ's notes) are very clear the levels have a linear progression, and that therefore there is no way for Siuan (or Leane as the case is here) to lose a third of their strength in terms of bulk quantities of the Power they could use.
What we then have to do is either treat it as a mistake or interpret it with in line with the superseding information from the guide.
This seems to have always been the tension here. You have always chosen to ignore the supremacy of RJ's own statements and only use your interpretation of the text. I let my interpretation be swayed by what the author says.
You are right that this is where the tension lies. But I think you are wrong in which side of the divide you put your trust. Because quite frankly, I think the people who wrote the encyclopedia made a hash of trying to interpret RJ's thoughts. In fact, I think they have misinterpreted his intentions by a wide margin in many respects.
The internal contradictions in many of their summaries, the superficial treatment of many aspects of the Power, and the clear lack of understanding of many of the deeper layers of the One Power in particular emerge clearly, from the various Q&A's they have conducted online, from the type of advice they gave Sanderson in his hatchet job treatment of the One Power in his books, and from the excerpts released from the Encyclopedia thus far.
For example, the very One Power strength excerpt you place great stock in, in fact does not state that Aes Sedai only occupy the 45 top levels. Instead, it states that Aes Sedai occuppy all levels down to level 72. I know you base the 45 Aes Sedai level conclusion on comments made by people who have seen RJ's partial notes in the library where they are stored, but this is a clear example of the people in charge of the Encyclopedia not understanding the importance of such a distinction.
We as long time readers and students of RJ's portrayal of the One Power are able to immediately pick up the significance of such mistakes, where these people do not have the insight to do so.
Another example is the rather self-contradictory statement in the One Power excerpt about the 6 male levels on top of the female levels not being of great significance in terms of the added volume of the Power that men can channel. And yet at the same time they claim that after the dexterity advantage that women enjoy, the net effect is that the strongest man and strongest woman are basically equal.
Well, which is it? It can't be both. Because if women have a big dexterity advantage, while the strongest man is not significantly above Lanfear in raw strength, then the strongest woman will in fact exceed the effective strength of the strongest man by a significant margin.
And again, this contradicts RJ's portrayal of the strength difference between men and women. When Asmodean was teaching Rand, he said the strength difference was in the same proportion to the male physical strength advantage. That is not an insignificant difference. That is a HUGE difference.
It is only the female dexterity advantage - which is of similar magnitude - that cancels this out. Similarly in RJ's own Q&A on the matter, he again said that men are significantly stronger than women, but that women outmatch men in the dexterity department by the same margin, thus allowing the strongest man and strongest woman to be more or less equal.
This is fundamentally different to the Encyclopeadia writer's asssertion that the raw strength difference between the strongest man and strongest woman is rather insignificant.
Therefore, another clear example of their lack of deeper understanding of RJ's One Power system.
How many quotes from the books need to be discounted before the lack of understanding of the Encyclopedia writers becomes evident?
Remember Aviendha stating that Egwene at level 8 is as strong as Amys and Melaine combined? That blows the linear 72 point strength scale out of the water.
Just like Leane's clear, undeniable statement that she and Siuan are well below half their former strengths.
The Aviendha reference to Egwene's raw strength compared to Amys and Melaine makes it clear that the 12 new levels added for the supergirls and Forsaken HAVE to be of much larger magnitude than the previous 60 levels.
There is no way that Elaida is at 83% of Lanfear's strength, let alone at 93% of Egwene's strength. It is flatly impossible. The list is not linear. Simple as that. Not if anything RJ wrote over the course of 10 books is to carry any weight.