A lot of what people have said in this thread is perplexing me, so maybe I should state a few of my basic assumptions about 4E, based on the things I've read mostly on this very site, before I get into the points I want to make. Or, maybe I should say the other points I want to make.
Assumption 1: 4e will follow a new paradigm of class balance. Based on what the designers themselves have said, class balance is in-combat balance, and they want to maintain balance across all thirty levels instead of having "power curves" like in previous editions.
Assumption 2: Class roles are a good thing. Apparently, this is a controversial statement, but honestly, I don't see the point of playing a class-based RPG at all unless there's a reason to have a group made up of different classes. Classes need to include specialties and restrictions, the specialties make you useful to the group and the restrictions make the group useful to you. The new concept of capital-R Roles is a reflection of the new focus of in-combat balance reigning supreme. A class should always have a clear-cut way of contributing to the success of the group, and the player should be warned ahead of time what the designers were expecting it to be when they wrote it.
Assumption 3: The designers are aware of and trying to avoid the obvious pitfall of Roles being too restrictive. MMO's were offered as a specific example of what they wanted NOT to do, in the particular example of "tanking" not being fun in the context of a tabletop RPG, and more generally in that they don't want classes to feel limited by their roles. Every class will be able to do significant damage and still contribute according to their Role, in theory.
Assumption 4: The designers will make mistakes. 4E will not be perfect, in fact it will even have some of the same boneheaded little bugs that every game has. Expecting perfection is just as naive as expecting total incompetence.
Okay, now that this post is already too long I can start talking about why I originally clicked the repy button.
I think there's a lot of different ideas of what "Fighter" means, and unless people suddenly become capable of all agreeing on every feature of a class that nobody's seen yet, it's just going to keep going around and around, so why are people being so hard on each other?
More interestingly, I seem to mostly see interpretations of the "Defender" Role that are very different from my own. Quite a few people seem to assume that a defender will only be good at standing near the squishies and keeping them from dying, and a fighter who runs over to the enemies and starts busting heads will be acting outside of their class role. This is not the impression that I get from reading the previews, playtests, and other designer comments.
My impression, and of course I could be wrong, is that mechanically a defender is someone who takes a small portion of the battlemap (i.e. wherever they're standing) and exerts a great deal of control over it. This control is exerted by being able to dish out large amounts of nasty badness on anything in melee range and by being very hard to kill. Therefore, wherever your defender is standing is a 3-by-3 block of YOUR territory. Groups can use this block defensively, by using it to block access to more vulnerable party members, or strategically, by placing it at chokepoints or flanking positions, or aggressively, using the defender like a grenade: charge into an area of thickly packed enemies, kill (or bullrush or whatever) them all, and suddenly you've harmed your enemy and captured enemy territory, assuming you're good at the "being really hard to kill" part of the Role.
Now, this is more complicated than is really communicated by just the word "Defender" but it does seem (to me) to be what they're doing. My point is all these options would still be fulfilling the defender role of staking out a little place and being king of the mountain, and are useful to the group in different ways. The shield and armor talents boost the "not dying" aspect of the role, the big weapons boost the "open a can of melee whoopass" part, and the control talents would give the fighter more options than melee damage in exerting control over their little patch of ground, probably like tripping, bullrushing, or some of the things the Knight class could do like render ground that's within their reach "difficult terrain" for the purposes of movement.
As for bows, well, there's no reason that fighters wouldn't be able to use bows, but I would consider it a grave mistake to make them as good at it as the class designed to specialize in ranged combat. Maybe you don't want to call the class that fulfills the defender role with armor, athleticism and melee skill a fighter, but that's a different argument to have and a moot point if we're talking about 4E. So what's the problem? I just don't get it.