1 - “The Undead can’t feel things”
The Undead have dulled senses of touch, smell and taste. Dulled, not absent.
“I love the smell of fresh foot scrapings, don’t you?”
-Argent Apothecary Judkins
2 - “The Undead can’t be happy”
Dumass, Professor Putricide and Calder Gray are proof that it’s possible for the Undead to be happy. Happy undead are rare though.
3 - “The Undead are incapable of love and sympathy.”
The Forsaken of Hillsbrad have become emotionally attached to the local spiders, which they treat as precious and beloved pets, like Baby.
Captain Jekyll also decided not to take Dun Garok out of sympathy for the Dwarven ghosts that inhabited the place.
4 - “The Undead can’t have “fun””
The Undead can’t reproduce, but they can have “fun”. Unlike Garrosh lol
5 - “The Undead are opposed to the Light”
The Undead are born of Death Magic, which is opposed to Life, not the Light.
The basic type of Undead created by the Scourge is weak against the Light, as it disrupts the connection between the Undead’s corpses and their souls. That said, there are other types of Undead.
Long before Undead Calia Menethil was a thing, we already had Fjola Lightbane, a Holy Val’kyr, in the scourge, wielding the Light.
With Legion, we met Odyn’s Val’kyr infused with Light to the point of glowing golden.
6 - “The Undead are extremely easy / hard to destroy”
This one is very complex. Undead bodies are more frail than living bodies and they can’t heal naturally. But they can also take a lot more damage before true death, and unlike the living they can easily replace lost body parts.
The amount of damage an Undead creature can take before dying seems to be very dependent on the individual. We’ve dealt with headless Undead before. On BfA alone, we saw an Undead survive being torn in half and another one being killed by a neck snap. It’s speculated that stronger willed Undead can take more punishment, but that’s not confirmed.
7 - “There are no benefits to being Undead.”
There are many benefits. You no longer need food, breathing or rest. And you can “live” forever if you take care of your body.
8 - “The Undead are inherently stinky.”
It’s very easy for the Undead to smell bad. Most of them have no incentive for hygiene. It’s not like they will get sick if they don’t bathe, and it’s not like they’ll get a date if they do. That said, it’s entirely possible for the Undead to not stink.
“The undead being who stood before the king of Stormwind was shorter than average but otherwise unrecognizable. The beard was gone. Cut? Rotted away? And the hair was dark with dried blood and ichor. He smelled like old vellum: dusty but not unpleasant. Faol had died when Anduin was a child, and the boy had never gotten to meet him.”
-Before the Storm
9 - “The Undead are strong against the Void”
While the Scourge managed to mine Saronite and build castles and armor out of it without falling to the influence of Yogg-Saron, it’s also known that being pierced by Saronite is deadly to the Undead. That’s why Sylvanas used Icecrown Citadel’s saronite spires to commit suicide.
I would say it’s a zero sum situation lol