1) More weapons/ammos/items in general
Not sure whether or not there will be "more" than what was in the previous games, but I would expect a fairly decent selection.
2) Either better AI on party members or better control over them (But not in the same way as in Fallout: Tactics)
This assumes that there will BE party members, rather than something like TESIV: Oblivion, which only has the player character and summoned/temporarily controlled "allies". But yes, I agree that if they do offer a party-based system, they should offer quite a bit of control over the party members, because otherwise what's the point? My vote is for a single-player, non-party-based system, however.
3) Very big world to travel, and also lots of different cities and towns to visit.
I think this can be expected, depending on what your definition of "big" is.
4) More variety to what NPCs looks like, it gets quite boring after some time when there are 5-10 different way character can look...
Assuming they make the game 3D using the same basic engine as Oblivion, this would mean that there would be a great deal of customization and variation of the way the characters look (both player character and NPCs); but then again, since Oblivion hasn't been released yet, this might not be saying much, since I can't sit here and say that this is the case when I haven't even played Oblivion yet. But from what they've described about Oblivion, it seems like they have a lot of options to choose from using sliders to change different characteristics, so assuming Fallout 3 goes 3D, I don't see why they wouldn't include something like this for Fallout 3 also.
5) More mutated animals and monsters to kill
See my answer to #1.
Since you brought up the previous games in the series, rather than just list off a bunch of specific skills and items from the previous games that I would like to see included, I will simply say that I would like to see most of the RPG elements from the previous installments (ie. the SPECIAL system, the skill system - such as computers, repair, etc. - and the character traits/attributes, which do things like making you resistant to poison/radiation, or give you fewer skill points but more ability points) make a return for Fallout 3.
As for the graphics, I've already stated my piece about that, but as far as the combat system goes, I would like to see a KOTOR-style pausable, "live-action-yet-turn-based-also" combat system, to prevent the game from becoming a simple FPS game since high rate-of-fire guns such as full-auto machine guns, rocket launchers, and rail guns will (hopefully) make a return also. KOTOR is a good example of how this type of system can mesh the use of melee combat (ie. the lightsabers and vibroswords from KOTOR) with the use of more powerful weapons (such as the blasters, repeating blaster rifles, thermal detonators, etc. from KOTOR). As an added bonus, it might also appease some of the "purists" who want it to be turn-based entirely, so as not to alienate them completely; not that I really care whether or not they are alienated, but the developers might

.
As for content, I would simply like a return of the adult-oriented, satirical content, along with some factions to join, and lots of interesting mutants to kill. I also think that this particular series allows for quite a bit of creativity on the part of the developers (if they choose to be creative, that is) in the types of world environments they can choose to implement. Someone mentioned somewhere once that an abandoned amusement park would be cool, and I personally think it would be cool to see the inclusion of an abandoned (or not-so-abandoned?) but relatively intact (or not-so-intact?) nuclear power plant or chemical factory. These are only a couple of ideas, as there are lots of ideas to choose from, so my hope is only that the developers don't hold anything back in terms of the variety of environments that will be included as well.
Edited:
Oh, yeah, and as far as #6 goes, I think it is a given that any consumer would want a game with as few bugs as possible (which is why I forgot to mention this one with the rest of your suggestions). Not that it's a bad suggestion, but it just kinda goes without mentioning. Also, for those who have been living in a fallout shelter for the last few years, KOTOR stands for Knights of the Old Republic by LucasArts.
2nd Edit:
KOTOR is also a good example of how you can have a party-based system and also 3D graphics at the same time.