It probably came from Braveheart or Highlander.
You want a big sword for stabbing and slashing? Seriously, go buy a sword of war. Any two-handed sword will work, even.
I'm all for adding more weapon variety into the game, especially for melee weapons (and some texture revamping for the old ones), but the way you're presenting your "suggestion" is dumb.
You can't even go through more than 1 horse hitbox and 1 character hitbox with a single swing anyways. That's just in M&B.
Going through 3 necks cleanly in real life is impossible, and I don't care what medieval weapon you have.
Do you see that? That's a piece of your spine. Your spine goes from right above your arse up to the base of your skull. It's comprised of your spinal cord, which is one of two parts of your CNS (central nervous system), vertebrae (bones that surround the cord), and intervertebral discs (which allow your vertebrae to move slightly and help hold them together). Bone is tough stuff. It's hard to cut through skin, muscle, and bone all in one swing, unless you have a big heavy weapon (given, a claymore is a big heavy weapon). You could probably get through one guy's neck, if he wasn't wearing a gorget (a circular piece of armor, from leather to steel, worn around the neck). Keep in mind, you're going through this:
If you're a big buff warrior dude used to swinging a big heavy sword, sure. I can see you going through that, even if you hit one of the vertebrae. However, after going through tissue and bone, you would've lost a lot of momentum in your swing. A ****-ton of your energy would be transferred to the bone on contact, and this would help break the bone, but your weapon would be moving slower coming out of the swing than going in to it.
In short: You slow down after you get through one neck.
Now, it would take a lot of strength and a really hard swing to get through one neck and have enough power to go through a second. It would take one really strong guy to get that done.
Going through three?
No.
There's no way you would go through three, especially if any of them had a gorget or bevor.