The game's title, referring to the year which it takes place, makes a lot of sense if considered an Allegory for the historical year 1776: the year in which The United States declared independence from its parent nation, leading up to The American Revolution a year later. In Jugdral's own 776, the Manster Peninsula is fighting for independence from its own empire, the titular Thracia. Suddenly, "In America!" makes a lot more sense.
In Thracia 776, lots of people complain that Eyvel is little more than a Jeigan despite her plot importance. However, in-story, there are several good reasons for her being that way. First she's a woman in her mid-to-late 30's, double the age of her adoptive kids; the only character in her same age range before she gets Taken for Granite is Finn (Dagdar seems to be in his 40's). Second, Eyvel has been a local leader and Team Mom for several years, which surely put a damperon her fighting skills since she hasn't seemingly used them for a long while. Third, and most importantly: Eyvel is not a swordswoman, but actually an archer; she isn't using the weapon she's most skilled at. Since she is Princess Briggid of Jungby, but can't remember it (and the only person in the Thracia cast who can make the whole connection is Finn, but he likely only saw her as Briggid from afar since he returned to Leonster with Quan and Ethlyn a few years after she joined the group), Eyvel/Briggid has been in this situation for more than 12 years at the very least, and even worse, she doesn't have her best weapon (the Yewfelle bow, kept by Faval). Considering these points, it's next to no wonder that she Can't Catch Up in-plot. (Gameplay and Story Segregation explains the rest from the outside: if Eyvel was at full form andhad her Yewfelle, she'd be a borderline God-Mode Sue.)
Leif seems to be relatively weak in Thracia, even if you compare him to other characters of his level. And his promotion gains seem to be unfairly low compared to every other character in the game. And then you realize that his promoted class is named Prince, the same class that he started with in Genealogy. Of course his stats are low; he is basically a Trainee.
Ranged staves in Genealogy have a range of 10 squares, but the same staves in Thracia have infinite range. This seems a bit strange until you start to consider the scale: for example, a standard castle in Genealogy is about 3-by-3 squares, and Thracia has indoor stages, none of which are larger in area than a castle (in fact, at least two castles you can fight inside in Thracia also appear in Genealogy). In other words, staves in Thracia probably do have about the same range that they did in Genealogy; it's just that the camera in Thracia is zoomed in much more, so "10 squares" seems like a much greater distance. Of course, then this raises the implications of characters inGenealogybeing able to traversemuchgreater relative distances with their Move stats...
Why do the characters who were introduced in Thracia 776 fail to appear in Seisen no Keifu, and why are they stuck with having their stats capped at twenty? Because of the difference in storytelling and the fact that most of the characters introduced in Thracia are militiamen who don't have the political importance or the holy blood to be relevant in more important fights like the liberation of the country of Thracia or the conquering of the Granbellian homeland.
Wait... but what about stat caps?
The units that you get in Seisen are soldiers who can take down armies; they're the strongest soldiers in Jugdral. While the ones in Thracia are really good, they're not that good.
In Thracia, Leif briefly mentions that Seliph has an army ten times the size of his. It's entirely possible that in Genealogy, the characters you play as are leaders of squadrons who all occupy the same tile. The squadron consists of people unimportant to the story, like the Thracia characters. Leveling up means getting more people in the squadron. note Characters in Genealogy who logically don't have a squadron when you recruit them (Adean and Dew were in prison, Deirdre would've been stopped by the other people in the Spirit Forest, Lewyn and Sylvia were completely alone, Shannan likely went in alone to Yeid and so did Patty) probably got one later when they leveled up. The characters from Thracia were all put into Leif's, Nanna's, and Finn's tiles.
The two unpromoted classes that can use both tomes and staves in Thracia are Shamans and Loptous Mages. They're essentially inverted yin and yang. Also, Salem can use staves because he's specifically mentioned to be a Lopt Priest.
In Genealogy, Ced's tome that he always would start with was the Light tome; however, in Thracia, all he has in terms of magic is his Forseti, but one look at Saias' inventory shows that he also has a Light tome. It's very possible that Saias gave him this tome to protect Manster, even in the possibility that he wasn't the prince of Silesse.
Saias has 10 leadership stars whenever he is an enemy at Chapter 17A and 22, but at the start of Chapter 23, he has 5 and when he's recruited, he only has 3. This would had made him a Game-Breaker if he has the 10 stars, but remember that on Chapter 22, he retreated whenever he was threatened and potentially lost the man who was said to be the second coming of the crusader Thrud under his command, so from the enemy's point of view, he was a coward and as such not saw him as a competent as they thought, and when he is recruited, they saw him as a deserter and a man who chose the weaker side, so the leadership stars are more of the enemy's faith in his strategic abilities, only to have his true abilities be revealed when he joins Leif and his army. It could also potentially because due to the Ragtag Bunch of Misfits that makes up Leif's army, they could not follow his commands as good as an army of trained and experienced soldiers.
Veld being very disappointing for a final boss can be attributed to a variety of factors: He rules only the Thracia region, so he's not in a high position as others in Genealogy, such as Arvis and Manfroy, who are more challenging to fight, he uses dirty tactics and manipulations instead of fighting directly for his own safety, such as a backup of other Loptous bishops accompanying him and using long range magic to his advantage, and finally... he's an ordinary human. The other final bosses in other games either have god-like powers, are closely connected to and are bonded with dragons, or are gods or dragons. Putting it simply, he's more fitting for a Geneology of the Holy War final boss for a late game chapter, rather than a final boss, period.