Here are some basic thought/ideas for Revamping Zones for your Private Server.
Contents:
1. Creatures
2. Objects
3. Custom Storyline
4. Example
More Comming Soon.
Creatures
Creatures are obviously the most important thing you need in the zone, so it's more life like, and players have something to interact with. Changing what creatures are spawned in the zones would change the area dramatcally, with display changes, if they're scripted or not, etc.
For example, in durotar you see those little piggies? If you removed them and added .. say .. demons, you could change how to whole area works in a whole, how the are looks like, etc because the player would be like "Why is everything gone, and we have DEMONS HERE!". They would wonder why and really want to level, see how everything else looks like, etc.
Objects
Spawns Objects in the Zone would also change the area as well, Say spawning Buildings, Mail Boxes, Tables, Chairs, Tents, etc would change the zone as well.
For example spawning a whole city with these objects would change the zone as well,
adding creatures to it and maybe a few custom quests as well.
The Core
Custom Events, Scripts, etc would also affect the zone as well. Custom cinematics showing the "Custom Storyline" progressing. Special "sound effects" for each "quest event" so the player REALLY does have that "at war with the burning legion" feel.
The core provides the ingame envirement alot of life, with scripts, custom AI life, etc. You can go wild here with adding custom values, etc.
Custom Storyline
Adding a custom storyline to your zone would also change alot in the zones history as well as how the players interact with each creatures, object, etc.
Example
For example, If I was to revamp .. say.. Durotar, I would remove every spawn in the entire zone.
Add Custom Creatures through the zone, maybe demons and some of the burning legion bosses with level 1 - 10 stats. Add some custom horde/alliance soilders, npc's for quest's, adding that "at war" look.
Spawning Custom Buildings throug out the zone, tents, etc. So the player's can really have that "expansion/ new patch feel" having a new area to play, somthing diffrent then the retail WoW they've played before.
Adding a custom storyline, saying somthing like the burning legion wants revenge for it's "strongest and most loyal slaves" for breaking free from it's "leash" and being free with the life on azeroth, etc so they invaded, blablablabla.
And at the end of the zone have a scripted event with the horde leaders attacking and pretty much PWNING Kil'Jaeden and the other burning legion beasties.
All in all, you may find this good or not, these are just basic ideas for revamping zones, changing how everything "looks and feels" etc.