Do you realize that every full sim has 268,435,456 cubic meters? That's right, with the new 4096 building limit there are hundreds of millions of cubic meters of space. And yet, because of narrow mindedness, many builds and builders are not taking advantage of what this means.
Consider that this means that even with 1000M between levels, it is possible to have three levels, each one forming a separate campus. Before campus systems, like Yedo's, created the interference with the sky problem, that with Windlight, is a particular concern.
The campus system simply uses a 256x256 solid prim as a floor, and then builds normally. When 768 was the limit, the trade off was having a floating high prim, which could be disguised somewhat, in return for having a great deal more space. However, with the new limits, a three tier, ground/middle/upper or two tier ground/upper system is now not only practical, but has compelling advantages. The most crucial being reduction in prim density while maintaining a physical plausibility and continuity.
The reason this is important is that a large part of client lag time, and user experience, is based on prim density and texture density. Prim density is how many prims are in the renderfarclip, or draw distance, of a client. Whether occluded or not, these textures and prims must be loaded. The twin tendency to pack prims to a sim's limit, and the faux-realist impulse of putting everything on the ground, meant that it was impossible, is impossible, to wander around these sims at more than 64M of draw distance.
This is because most people, including many highly paid builders, do not understand the concept of prim radius. The prim radius is the taken by the number of prims that a particular client can load, divided by the prim density. This density is really an amount of time to load, which is a factor of number and size of textures and prims. More prims, with more textures that are larger are slower. People set their draw distance down to their prim radius, or to their level of pain tolerance for loading time. People who play SL on large fast machines with geekgasmic video cards see SL differently from people who play SL on laptops and smaller machines.
This concept means that very packed sims do not have a "better" experience, but instead begin to break up into very small areas, and become claustrophobic. This increases perceptual size to some extent, because it takes longer to cross the sim, but also increases frustration. Particularly for stores. Packed sims have people wandering in 64M bubbles.
The old campus design created more openness, at, again, the cost of faux-realism sense of geography. Now that this limit is easily avoidable, the advantages of spreading prims out over larger areas, and therefore reducing prim density. This means even slower machines will be able to have longer draw distances, and be able to see greater effects and distances. Combined with huge prims and core and floor design this allows for dramatically large spaces and more focused ornament.
In summary, the 4096 limit should be used to dramatically decrease clutter and prim density, increase the amount of raw land area in a sim to 32 or even 48 acres, and improve perceptual lag while increasing usable client renderfarclip, without detracting from the sky effects of windlight.