I think you guys are making it really confusing and strange.
Maybe I explained it in a confusing way. To sum up:
Press number 3: Normal rifle mode, no bayonet
Press number 4: Rifle with bayonet attached +less accurate shooting
Press number 5: Only bayonet.
Going from 4 to 5 takes no time.
Going from 3 to 4 or 5 takes a little time since you have to mount the bayonet.
Unless it can be done like this i don't want to see any changes.
It can't be done like that. Elaborating on Kev's post, I believe you can only have one "deploy" animation per weapon. I.E. No matter what, "4" or "5" will either always show you attaching the bayonet when you switch to it or having the Bayonet magically teleport onto the barrel instantly, regardless of which number you had selected beforehand. This is why you never see the soldier removing a bayonet or Rifle-Grenade Launcher from his gun in-game now. You can only have one animation per weapon that plays when you switch to that weapon (related: you can only have one reload animation, which is why you always reload a full stripper clip [or two for Enfields] even when you have a few rounds left in the internal magazine).
Can we do anything with the "Fire Mode" feature (the one that lets switch between Full-Auto and Semi-Auto on certain weapons)? I'm assuming that the game treats both firing modes as the same weapon (even though there is a small animation [usually flipping a switch, I think] when you change firing modes), so I don't think it's possible with the "one projectile per weapon" clause.
Is there a way to make the model of the weapon itself dangerous (or actually, the bayonet part of the model)? Like, you could switch to the bayonet, still be able to shoot, but less accurately, but also be able to hurt people by just running into them (or more specifically, just making the model of the bayonet touch them)? If that's possible, would it be possible to make the damage proportionate to how fast you are going (i.e. it does more damage if you run or sprint into them then if you just stand in place and wave your pointy thing around)? Of course, this would make multi-man bayonet charges more dangerous, because if someone twitches the wrong way, he could stab his buddy without actually pushing any button.
I'm just trying to get some options out there. Like Kev said, if there is the slightest chance of something working, we should get it out there in the hopes that the Devs could get it to work.