Hugh is a level 15 unpromoted mage when he joins, yet has growths near the levels of a prepromote. Why is this? Because he's just not that mature! He's a grown man who still acts like a child, so if he was more mature, then he would've already been promoted.
Plus, Hugh may have inherited his mother's huge skill for Anima Magic... but was raised by his grandmother, who is a Druid aka specialized in Dark Magic instead. Niime simply can't draw out Hugh's whole potential no matter what, his magic skills lie elsewhere.
Why is Eliwood so powerful in the Trial Maps? Because he's not ill anymore! Or at the very least that's what his Trial Map incarnation is going for.
If Ninian is Roys mother, then Roys belief that humans and dragons can live in peace takes on a whole new meaning, as Roy himself is proof of this.
Why are Cecilia's stats surprisingly low when she joins in Chapter 14? Well, she suffered a critical from Zephiel last chapter, and even if Cutscene Power to the Max was active to let her survive, her surviving unscathed would just be plain ridiculous.
Tying into the last entry, the reason Narcian and Flaer were unable to take Cecilia's castle and thus making Zephiel do it himself is because Cecilia is in top condition, having not suffered a grievous wound, and that she has Aircalibur while Narcian and Flaer are low-resistance fliers. Of course they haven't defeated Cecilia - Cecilia would tear them apart.
What if Roy is a quarter dragon manakete. If Ninian is his mother, this is the reality. He can't transform because he doesn't have a dragon stone. Also, if he is quarter dragon he will outlive everyone but Fae and Sophia.
On the other hand, Sophia is never shown with a dragonstone, either, implying that some manaketes are okay with not transforming. Additionally, her and Fae's supports imply that part-manaketes don't live quite as long as full dragons do, softening the potential problem with Roy slightly.
If Ninian is his mother, it also presents one other piece of fridge horror: Roy is going around killing other dragons possibly without knowing he himself is part dragon, making him an unwitting Hunter of His Own Kind.
Hector's death in The Binding Blade is a Player Punch already for those coming in from The Blazing Blade, but remember that he almost certainly had his most loyal retainers with him in that battle. That's right: Oswin, Matthew, and Serra were most likely killed off-screentrying to protect Hector, and their sacrifice still wasn't enough.note (No matter their canonicity or lack thereof, the novels apparently state that Oswin did die in the same battle that took Hector's life...)
Juno's support with Noah reveals that her old rival was Sigune, the Flightleader at the time of Roy's invasion of Ilia. This means that you unwittingly killed one of Juno's closest allies.