world
You're right on most of your perceptions of the games' landscape / architecture.
Prophecies - mostly medieval / european architecture. Much like standard RPGs, there's the mandatory snow areas (Shiverpeaks), deserts (Crystal Desert), fiery/volcanic areas (Ring of Fire) and jungles (Maguuma / Kryta). The areas are huge, and offer much varied scenery.
Factions - architecture and landscape is asian (Cantha = chinese / japanese), German/Gothic (Kurzick) and Luxon (aquatic? lol can't really tell). A big chunk of the game is set in a claustrophobic, overcrowded, multi-tiered slum. Later on though the countryside opens up and you see great forests and a sea turned to jade
Smallest of the 3 chapters in terms of area.
Nightfall - North African theme - drylands, savannahs, caves, oases, gorges, deserts. Then later on, twisted representations of the "normal" places. 2nd largest in terms of land area.
Population -- it's gonna be either Prophecies or Nightfall, plenty of people to play with up until the latter parts. Factions seems deserted halfway through. Most of the missions and quests can be done with the NPC henchmen, though.
If a "population" of a town is "full", say 200 people, there will automatically be created a second District to catch the spillover (e.g. Ascalon City Dist 1, Dist 2, etc....) If you feel a district seems overcrowded, you can just move to the higher-numbered districts for some peace and quiet
However, GW is an
instanced game. You only meet other people when you're in towns and outposts. Put a group together, and when you go out of the town, GW will make a "personal," exclusive copy of the area. You won't see anyone else except those you grouped with. This will seem lonely, but is designed to eliminate spawn-camping, loot-stealing and other negative stuff that seems common in standard MMORPGs.
Your concern about population is valid, as it'd be fun playing with others online. However, the random pick-up group (PUG) is a mixed bag, ranging from idiotic/horrendous to a brilliant showcase of teamwork and skill. You can also use the available Henchmen NPCs in town, to fill in some of the group. Best join a guild so you can ask guildies for help (after all, this is guild wars).
With the arrival of Nightfall, it featured Heroes -- customizable companions. This took away the problem of waiting forever at towns to get a good group together or if you don't have anyone who is going your way too. You can pretty much play by all yourself with 3 Heroes and 4 Henchmen, or you and 7 Henchmen (max people in a party is 8 persons) throughout all 3 chapters.
My advice: see if you can get a 10-hour trial code, hopefully 1 for each chapter and try the game yourself. Granted, 10 hours won't get you deep enough into the game to really see the scenery, but hopefully you can get a good feel of the game.
As to choosing which to buy, here are some points:
Prophecies - Tons of free skills given as quest rewards. Gentle learning curve.
And as it's the oldest, hopefully it's the cheapest now too. My pick if you want to start.
Factions - Most skills have to be bought. Faster character development and learning curve, feels rushed though.
Nightfall - newest, so the one nearest the original price. The Heroes feature is its biggest attraction, which can really help a lot when you eventually decide to buy the other chapters and play in the areas where there are no other players. For this reason alone, this is my second pick.
An upcoming Hard Mode (set for release this week, I think) to be implemented throughout all chapters will make it more difficult to rely on Heroes and Hencmen alone, and may see a resurgence in pick-up groups.
Hope I haven't overwhelmed you with this long post. Feel free to ask away, always good to see people interested in Guild Wars
