Alot of people were thinking that Guild Wars should aim for a 'Greek/Roman' theme for the next chapter. We've already got a kind of European classic fantasy with a hint of Norse, Asain, and African/Egyptian/Indian theme. The logical next step is to aim for something new: Grecco-Roman stuff.
I disagree. I mean, we fought a Lich Lord, a betraying Envoy, and a freakin' God. How do you plan to top that? Fighting a corrupt Caesar would be kind of anti-climatic after facing off with a god.
So here's my idea. I'm not going to plan out everything, like some people do with new class ideas. I'm just going to give the general taste of what I was thinkin' and start naming off stuff that would work.
We should have another Guild War. The Jade Brother hood as this kind of evil guild that pillages Kaineng City. That was neat. I liked fighting enemies that had capes. Let's go one louder.
* Mutliple NPC based Guilds from multiple places. A Luxon Guild, a Vabbian Guild, a Shining Blade guild. No single enemy.
* A PvE side to being in a Guild. Special Guild Henchment that wear your cape. Special Guild NPCs (Think non-party memebers who are in your group, like the occational quest that gives a couple Sunspears.) that can come with you to battle.
* Allied mobs. Turn regular locations into all-out war-zones.
* Other live guilds having enemy mobs. It could be PvE vs. PvE.
* Larger Guild Halls that can be attacked by NPC teams.
Edit: Additional Ideas
* The ability to join NPC guilds with an Alternate Cape option. Let's face it, some people are in wonderful guilds with not-so wonderful capes. I'll tell ya, I'd switch my cape out for a Jade Brotherhood cape anyday.
* When NPCs attack your Hall, it can be set up as a mission with skill point based rewards on how good you do. And then to keep it new, there could be differen't types of attacks. Like one where you just have to defend your Lord, or one where you need to kill the enemy lord, or even one were it's like Victory or Death and you need to do both. Any other ideas pretaining to this?

List of ideas for the backgrounds of the said NPC Guilds:
Place: Like a Kryta Guild, or an Ascalon guild, or a Vabbian Guild
Faction: Like a Lion Guard guild, or a Sunspear guild, or guilds for each of the Factions sides.
Race: Tengu, Centuar, Forgotton, Harpies, Undead, Charr (<3), Human, Dwarf etc.
Leader: Mhenlo, Verata, Jarto (Hey, he popped up in Nightfall. xD), Talon Silverwing etc etc
God: All five. Heck, maybe even Abaddon too.
Those are what I have so far. And shit, the whole Grecco-Roman thing can still work. Rather then one big island with a smaller 'noob area', how about a series of islands. That'd fit into the whole Guild War thing, since Guilds own islands anyway.
Anybody with anything else to add, go nuts. We can only influence Anet, not dictate what they need. I'm stumped on classes, but let's make sure we get some real casters in there. We have three melee classes and two ranged physical attackers. MAYBE another ranged physical attacker.