I have seen what a wither can do first hand. First time was with my faction's farma base, it was inside the innermost wall within 15 minutes of it being spawned in. There was no defense against it, within minutes every part of the base was blown into and the farm was rendered useless. I have seen Aegis's mushroom and pumpkin farma base after it was completely obliterated by a wither, as well as Insiders base being destroyed right after the walls, went up. The results of these wither raids are devastating and have caused many players to give up such as the entire 4th Reich faction; which at one time was one of the most powerful factions on the server.
Brad made an interesting suggestion as did Parot4ktv however I do not see how either of these ideas will work or be successful. Also as for tnt cannoning goes I have broken into countless claimed vaults and bases with a simple tnt slime stack cannon, can you cannon into a huge base such as Misfits or Aegis? Yes. Will it take multiple slime stack cannons, people, and time? Yes. Personally I have found that the faction aspect of this server is absurd; I think it's cool that it allows players to make connections with each other but it creates a single powerful group that guarantees the destruction of all other factions.
My suggestion is to remove factions from and extend the map to a higher boundary such as starting the map at 15,000 blocks and increase by 1000 every month (open to debate this is merely a baseline). With the implementation of farmm I really like how there are no factions and bring the game to what many players desire it to be. I have noted many people wishing this server to be more based on farming rather than a faction shit show where your base gets raided minutes after it is finished *cough* Insiders faction base. With the current system, it's very difficult to grow, sell, and excel if your base is wither raided to the point of destruction, especially before it's even finished or shortly after being made. With a map extension more farms can be made hidden from other players and will balance the removal of factions as land will no longer be claimable.
This being said, another suggestion would be to take it in the exact opposite direction. Increase the amount of players that can join a faction and increase the faction power of each rank (another player suggested the former of this idea earlier). Extending the map would still be necessary as more land would be needed to accommodate these factions.
I understand these are extremely radical ideas and would basically change MCDrugs completely. I am open to constructive criticism and would love to hear other players thoughts on this.