Post your ideas & suggestions for the sequel. 

My suggestions:
-There should be more vehicles (helicopters would be disturbing online, but jetpacks with limited fuel would rock.
what about submarines and parachutes?)
-There should be something like a grappling hook for some special moves. Thermal goggles will be useful if there's gonna be
much vegetation. Pop the enemies' heads thru the woods. 
-More stealth weapons would be cool.
-The game setting should be a more futuristic (something like in the game "Crysis" would be cool. An antarctic setting would be great, too;
i'm sure swimming below the ice and pulling the enemies down there would be fun)
-More Buildings!! And make them all accessible.
-Underwater equipment would be awesome.
-More diversified missions are welcome.
-The host shouldn't be able to ban people, and noone should be able to ban anyone by voting! If someone is team killing the game
should ban him automatically.

That's enough for now; I might update this list as soon as some ideas pop up.

I think there should me way more pieces in the map maker.  But not complex pieces, simple pieces, ex: walls, floors, doors, appliances.  I want metal stairs, metal and other flooring of all different sizes and shapes.  Brick and other types of walls in all sizes and shapes.  Buildings to block/prevent shrubs and grass from appearing inside. 

***ALL OBJECTS IN THE EDITOR THAT DO NOT HAVE PHYSICS PROPERTIES- SHOULD ALSO ACT AS OCCLUSION BLOCKS***

The ability to flatten object groups to a single (and now un-editable) combination object to save memory.

Multi-layered water levels.  I want a lake in the mountains with a waterfall running down.

The game to just draw some random backgrop according to the map properties, so that you no longer see the edge of the map while playing, just editing.

The ability to totally remove the ground so space scenes don't have to be manipulated with occlusion blocks.

Airbrush and other coloring tools for the editor.

I know my wish list is getting too long so I'll stop here.

-More vehicles! at least 8 vehicles each team
-a good clansystem
-and like captainDEEZ said, more objects in editor to build custom buildings/structures (difrent walls, doors, windows, stairs, etc)
-unlockable scopes etc for weapons (something like cod4)
-ability to customize your caracter (something like in socom or rainbow6 v2)

 :

MORE PEOPLE ONLINE!!!

-Ability to place weapons. (I don't really like the classes system in FC2 too much.)

-I want the predators from the earlier Far Cry.

-Ability to enable physics on any object. (Ex. You make a skyscraper with concrete blocks and iron beams, and when you jump in multiplayer mode, and shoot a bomb at it, it will collapse and fall into little bits.)

-Decals, lights, particle emitters, and bots.

-More themes for your levels. (Everything being African themed is kinda boring.)

-Triggers (Like when you walk into a trigger area and it activates something, like spawning an enemy behind you.)

-More weather effects. (Snow, rain, fog, lightning, dust storms, sand storms...)

-Something faster than ladders and stairs...

-Zip lines.

-Ability to emit captured object(s). (Say you make a cluster of rocks. You save it in some kind of map editor inventory system, then you place a switch thingy that will shoot the object(s) you captured in the inventory.)

-Parachutes.

-Water that hurts. (Jumping off a bridge that is a mile high into water shouldn't be possible to live through in games.)

-Scale option for objects. (Like for making bigger trees, or for making a giant enemy that will destroy whole buildings. )

-More lighting options. (Such as making everything black and white, adding bloom, or making the sun glow red or purple.)

-More skyboxes. (Instead of having just clouds in the sky, it would be cool if you could make some alien like background with multiple planets in the distance.)

-Character customization.

We'll, that seems to be all I can think of right now.

I want a quick knife button like Call of Duty.  Can I press R3 and instantly stab somebody?

Another thing I would really like in FC3 is the ability to lock your level so other people can't edit it.

I keep finding my level MAG TOWN everywhere, except under a different name, usually barely or not changed at all. One map I found "City with real Textu" I think that's what it was called, was barely changed at all from the original MAG TOWN. (I think all they changed was the texture on the ground.)

"City with real Textu" is on the 3rd page of the highest rated (I think it's the 3rd page.) Although my original has 3 and a half stars. (I need to host more, but nobody ever seems to join.) It's cool how my map (although edited) has such a high rating, but it's disappointing that people play it and it appears to be made by someone else.

Btw, MAG TOWN once was on the second page of the highest rated list, but not anymore. 

It would have to be right in the eye for it to look remotly realistic.