Realism I do not care about (though do not object either as long as it does not intefere with proper gameplay too much). Guns expert persons would be happier if what they got, made a difference, don't you think?
They do make a difference imo, if you're fighting a high DT enemy, AP rounds can cut down on ammo usage and kill the target faster, thus making combat easier.
And I certainly don't think different ammotypes help the general balancibng of the weapons with all the new and different variables.
I see it as they make lower tier weapons capable of doing decent damage when wielded by a higher level player, for example I still use a 10mm pistol even on my level 50 character, and the only reason combat is possible with this weapon against leveled enemies is because I use AP and JHP rounds. I carry the 10mm for RPing purposes, and while I do have more powerful weapons in my inventory that I could switch to, I prefer to use the weapon that makes more sense with the background that I've written for my character. So the variety in ammo types does help to balance the weapons in some way, although you are right in that they add a
ton of new variables.
HC mode I agree with in general, but if the ammotypes do so little, what good would they do in the HC mode?
Take my example with the high DT enemy, the AP rounds cut down on ammo usage, thus cutting down on the number of rounds that you need to carry. The AP rounds also let one weapon be more versatile against different enemies, potentially cutting down on the number of weapons you need to carry. Most importantly, the AP rounds help to kill the enemy more quickly, thus cutting down on the time that he has do damage you, which is more important in hardcoe mode because of the lack of instant healing.
That's all well and good, but the characters choice of weapon does not make any difference unless he chooses close combat. Basically, there could be just "close combat" and "ranged combat" skills. Back up weapon does nothing in practice, as you can change your weapon from the inventory at your leisure even in combat. The whole combat system needs rehauling - not towards a better FPS (like BF 3 or such) but towards a better RPG, slower and more reactive to the characters skills.
By "backup weapon" I meant to say that this character only carries sniper rifles and handguns. And I disagree that the character's choice of weapon doesn't make any difference outside of close combat, I mean an anti-material rifle is more effective at long range than a trail carbine and an AM rifle with explosive rounds is more effective at range than if it were using regular rounds.
As for combat in general, I like the way it is now, with a choice between FPS and slower VATS combat, but I think VATS needs to be overhauled. Like you said I think it should be more reactive to the character's skills, and I also think that choosing VATS should make that combat session completely turn based. For example, if you take four turns and drain all of your action points, then your character should stand idle until your enemy(ies) take four turns before you can return to FPS mode.
I don't know if that would work out, but I always thought that VATS would work better that way.