DragoFireheart: Don't touch my swords, man. I can still remember up to when I was about 5 years old holding a plastic sword over my head and shouting, "I HAVE THE POWER!" If RPGs can't be used to recreate the childhood He-Man experience they should be wiped from history LOL!
But seriously, one of the main things that JRPGs have is younger characters. I think there are a whole lot of wrong ways to use younger characters like over-sexing them or making them like ten (where you wonder why anyone would let such a young person go out into the wild to get horribly marred to death by monsters). The right way (at least from my observance) is to show that the young characters can take care of themselves (usually showing that they have become badass while everyone else has kinda been a slouch in their combat training compared to the character), have worth in society (they've made large and small changes for the better in the world), and/or are trying to see the world through a new lense (I really tend to like this not go with the flow and be jaded like everyone else attitude). Another reason I think young characters are good for a JRPG is that some of my favorite stories ever have young protagonists (Peter Pan, Avatar: The Last Airbender, The Chronicles of Narnia, Pay it Forward, Harry Potter, Animorphs, etc.).
Between the "No angels..." and "No pallette swaps...," it's really a toss-up if any of those things apply. The angel thing really made sense for Kefka and Sephiroth (Final Fantasy 6 and 7, respectively) because Kefka wanted to be looked on as a god (whose entire theme is based off "The Divine Comedy," and so decends like a fallen Seraphim in his final form) and Sephiroth litterally wants to be God (in this case the planet, Gaia, by merging with it), but Sephiroth's final form, Safer Sephiroth, is angelicly related through his name in relation to the Bible (the name of his final form roughly translates to "Book of Numbers," and the themes surrounding him throughout FF7 have a lot to do with numbers like those tatooed on his genetic slaves or how Shinra Corporation hoped he would lead them to "The Promised Land" just like Moses in that book of the Bible he's named after).
As for relatable antagonists, eh, it depends how much you read into them (and it helps if you think they are cool/exciting to start with). Take two of many peoples' favorite RPG antagonists, Jon Irenicus and Kefka. I, personally, don't get Irenicus with the whole love of the elf queen yet somehow lusting for power, which makes him do something unspeakable and changes him for the worse forever (even though the elf queen says he's not the man she once knew it just feels so out of left field like Bioware just tacked her on to "humanize" him when they really just needed a character seeking godhood, IMHO). I just don't get any sense that Irenicus was anything but creepy as there is just not enough about him to resolve the questions that nag me about how his love affair with the elf queen contributed in any way to his motivation to become a god. Though, David Warner did do a hell of a job with Irenicus' lines, especially during the scene where he is getting arrested.
Kefka, in contrast has much less lines and information about him but the same goal. However, he does have a consistant character that constantly makes the suffering he puts upon others sound like a laugh to him. He is completely arrogant and uncaring of others while at the same time making it entertaining (it's like Mark Hamill's The Joker). Kefka also has a foil in General Leo throughout much of the game. Despite being on the same side even soldiers of the empire they serve lament how opposite the two are. Then there is some intrigue created by a piece of dialog slightly hidden in the game world that Kefka lost his mind because of being the prototype for the empire's magitek knights before the process of magic infusion was perfected. So we may not know who he was before the events of the game, but by the end we know Kefka's entire god-complex was partly obsession with his own growing magical power and partly because he is an extreme nihilist wanting to make everyone believe in the meaninglessness of everything and worship him so that he might bring finality to a worthless existence. Again, how much you read into a character matters a lot when trying to understand them.
The only other point I wanted to look at is the guns being more lethal than medieval weapons. I'm pretty sure that a guy with a gun is more likely to kill someone than a guy with a sword. Modern guns have high rates of fire, large clips, and range on their side. However, one can't make you more dead than the other and both can induce countless different injuries in varying degrees of lethality. In a JRPG this shouldn't count for crap, though, as gun or sword is just a skin over some hopefully fun to play around with game mechanics (I think Phantasy Star 1 handled melee weapons and guns pretty good). Guns and Swords in video games may be a tired trope, but it still feels interesting to have that dichotomy of old vs. new but on equal terms that real life lacks.