I can't answer for Wik but I generally use the same era as a basis for my own campaigns. And like Wik I allow in non-period armor and weapons but try to keep the atmosphere the same.
What I've learned is that the important aspects of pushing the feeling of the time is more demographics and political structure than anything else. You need to emphasize the smallness of the civilized world and threat of the vast surrounding wild. All the various little thorps and farms and peasant villages you usually have PCs run across as they go overland aren't there. Settlements are tiny islands of civilizations in a howling wilderness overflowing with monstrous threats and barbarian tribes. The barbarian tribes and their constant threat to civilization are very important to the feel. Get rid of the teleporting to force overland travel so that players are confronted with the wilderness and the vast distances between any settlements.
Populations-
First of all you can use any settlement size above thorp but try to start at the larger end of Hamlet. A settlement any smaller isn't able to survive in the face of the threats of the wild and barbarians. Above that size any of the DMG categories are fine as even in the ancient world there were massive city-states right up to the metropolis level. The key to maintaining the feel is to spread them out. This you do with demographics, take the land area of the region to populate as best you can approximate it in square miles and multiply that by .6.
This is your total humanoid population now divide by half for the number of civilized peoples all the rest are barbarians. Now to plan settlements 90% of these will be in hamlets and villages(75/25 split) and the remaining 10% in anything larger. The key is spreading out the individual settlements. It should seem as if the very world resents civilization and the larger a settlement the more it attracts threats to itself. The bigger your city the more howling monster infested, barbarian overrun, of a wilderness surrounds it and the more dragon attracting it is due to its wealth and prominence as a glittering treasure filled source of loot.
Two numbers for each settlement size the first is the radius it actually controls and inside this the population density should be roughly medieval(~120 adults per mile^2). The second is how much distance between it and the next settlement. Area not inside the controlled radius of a settlement should be considered your standard monster infested wilderness full of bloodthirsty ravening barbarian hordes. Hamlets and villages are in Group A and should be the recommended distance away from each other. All larger settlements are in group B and should be the recommended distance away from each other but can ignore category A settlements for this.
Figures are in miles
Group A
Hamlet=1/14.5
Village=1.5/20
Group B
Small Town=2/30
Large Town=3/43
Small City=5/67
Large City=7/100
Metropolis=12/163
Governments-
There are no kingdoms yet, though there may be empires those should be used very sparingly as well. Settlements in Group A should be run as if one step out of the neolithic. There are still strong tribal tendencies and clans but a single ruler, his rule is not strictly speaking absolute as he must pay attention to the various powerblocks within the settlement but it will be hereditary. This ruler will need to use personal force and the action of household forces to maintain his position and standing as well as be prominent both in ceremony and defense against outside threats.
In Group B things can be split into two categories, towns and small cities in the 1st and large cities and metropolises in the second. Towns and small cities are ruled by hereditary dictators. These should always be the single most powerful(highest level) individual in the city and probably a primary caster. Rule is maintained through personal power and imposed harshly without reservation. There should be lots of slaves, many more slaves than free citizens let alone nobles. These slaves work the lands of the nobles, and in the households and workshops of the free citizens who each have a couple at least. The dictator will have the largest standing force of arms in the city with nobles having their own smaller guard forces and even wealthier free citizens managing a few guards. Magic is power and the power structure will most likely be magocratic to at least some extent with military retainers.
Large cities and metropolises are the easiest and hardest to do. CSIO is a great resource, so is any references you can find on the various Sumerian and Akkadian city-states. The difficulty comes in adjusting for magic. The power structures should be roughly the same as historical at this level for the period. But it is absolutely key that the higher a position you hold the higher level you are, otherwise someone else would have killed you and your family and taken your place. Expect concentrations of primary casters at the high echelons of society. At this level you get bureacracies to support the king, big ones. Essentially a triangular power structure with the king in one corner, the nobles in the second, and the priesthood/bueaucracy in the third. They're each almost equal and that forces them to balance each other out to prevent collapse. Huge slave labor populations under the priesthood and nobility as well as the king.
For laws its best to go right to the source, the code of Hammurabi and of Nebbuchadnezar(not the Egyptian one the Akkadian one sp may be off) are great for concocting laws that'll give your campaign that ancient feel.
