What I think Demacia is like
It's made pretty clear that Demacia is all about justice. Which means that Demacia is a land of law, and order. While these laws do somewhat inhibit the growth of military technology, they're only there to restrict evil laws, like that of the deplorable human experimentation going on in Zaun. These laws do reduce Demacia's military technological development, but more than make up for it as it's greatest recruitment tool. It gives Demacia the moral high ground; Demacia fights for good, and Noxus is the evil to be exterminated. Naturally, a new enemy for Demacia is a blessing to it's military leadership. This exposes an inherent hypocrisy to the Demacian military. Military leaders have a incentive for finding more "evil" to destroy, as when they do, they become more powerful. This means that we can expect Demacian leadership to secretly foster conflict for their own agenda.
Other than that, Demacia's a pretty normal place in it's time; The strong still pray on the weak in whatever way they still can. There are probably much more restrictions than a normal country for the sake of justice. (it's probably getting a little out of control at this point.) I personally believe that government intervention always fails, and ends up hurting the people you are trying to help most. Laws may restrict the powerful from abusing their power, but they also often tend to restrict the weak from gaining any power too. That's why I imagine Demacia as a place where the poor stay poor, and the rich stay rich. It may be a stable country, but it's an inefficient country. (It would explain that why Demacia has many more allies and territories than Noxus, and still isn't flat out winning.) Also, like all kingdoms, government tyranny is always a looming problem; Especially in one that likes to make a lot of laws. Luckily Jarven IV appears to be a benevolent, and effective leader.
"Demacian worms! They parrot kind words, but they are ruthless all the same." -Sion
, this child lives in his own world of heroes and villains, while shouting his own name, Demacia or Justice, seems like he hasen't gown up, i could spend so much time on why I dislike Garen, but this post is not only about him, but keep in mind that he enbodies what is wrong with Demacia, probably more than any other Champion from Justice place.)