Check your math
2k from other kings
3k from original skulls
And 3k from lady in wights
Aka. 8k king of skull servants + combined with potg and anti spell arrow for the win it will be a game ending farm ooh i got an idea now for my farm deck
8000 isn't a very useful number for farming. It's still below 10k, so you still need to increase its ATK or use an extra Union Attack. It's also pretty slow. It's pretty easy to drop a 4k+ monster much faster than even a 3k King (barring lucking out with Grass or Veil). And even then, we're long past the point where farming decks use stuff like Master of Oz.
Nobody. But that is not at all relevant to my point. It's ATK doesn't get high enough that it has an advantage over a card like Master of Oz, which is easier to Summon and takes 3 deck slots as opposed to 8+. The only "advantage" would be being able to run Veil of Darkness as a deck thinning tool, but then, you could just run Shard of Greed or Good Goblin Housekeeping or whatever in a better deck.