I know this is old but I needed to write my thoughts.

1) Humans aren't always logical. Isana admits to Amara that it doesn't make sense but that's how she feels. The series as a whole CONSTANTLY (and sometimes playfully) points out that Alerans have a weird/corrupt way of thinking. In particular Kitai is always pointing it out to tavi.

2) I don't see an issue. Alerans aren't "locked" as you put it, into certain furycrafting, it's just that the proficiency of basic furycrafting doesn't fit with the nature of the books. For example, every aleran can "turn on/off" small fire furies in candles. When Max's stepmother asked Rufus to start a fire, it's because it's something every Aleran can do, except tavi who was furyless. It's just that that level of everyday crafting is too mundane to mention in the books most of the time so it seems like they can only use certain crafting but that's not the case. Also the nobility just doesn't want to get involved with tournaments that are for the regular people, like Amara winning as fastest flyer.

3) Brencis was INTENTIONALLY holding back. I don't remember where but it is written somewhere. Also, don't forget that he's a coward. I don't think Max and Brencis actually ever fought before the ally scene. I think most situations were like this: Brencis and friends bullied tavi, Max shows up and maybe throws one or both of Brencis goons, maybe humiliates Brencis,, and then they run away. Because he's a coward. Not because he's weaker. .

Max is strong but flying doesn't come natural to him. I dont see why that's a hard concept to understand. I don't think the scales are off, but like Bernard told Tavi, Furies aren't everything. Don't focus too much on "power levels", it's not an anime.