For this case I give +1 as the moment someone adverts kingdom raid everyone in the kingdom basically moves towards the base defense and the raid can be over in seconds + the fact that the king can have laws where their party can KOS unwanted people, so having kingdom raid advert gone it would balance the problem
I would also HUGE +1 this as there is not really an easy/accesible way to counterplay cereal. For new kings or people that are experienced with being king, being teleported and instantly killed may ruin their experiences for the people living in the kingdom and for the king itself. Also that cereal is super easy to obtain by fishing or buying it people can non-stop use the cereal to tp the king and kill them to take their spot.
For this I would give a NEUTRAL as I do think having a random teleport area would give raiders a better advantage of raiding and reduces the risk of being stuck or having the entrance be spammed with leggies and ending the raid, but only if the teleport spawn is around the area where you can't build, not all over the entire kingdom. Having the spawn all over the kingdom gives the possibility of raiders spawning in homes already in the kingdom that'll already give them a huge leverage and most experienced raiders will come with sbcs, jetpacks, etc, so they would already have bypassed the entire kingdom defense, making it useless like you said and will have no point in having the base defense. But if you make multiple spawns around the area where you can't build, I think it'll still give more opportunities for them to have a successful raid and making the chances of them dying lower. What could also happen is that you could make the no-build area bigger so then they would have to make the base defense bigger, adding the new multiple spawns would give them much more space to breathe in.