Maybe it's just me but I think golden apples are very overpowered. In op-half you can just keep spamming golden apples and new armour and you will never die. I think that Cubecraft can make the golden apples more expensive. In Op from 3 to 8 gold and in Normal from 5 to 10 gold, I don't know the price of golden apples in hardcore. Also the golden apple kit can be reduced from 2 golden apples to 1 golden apple to make that balanced as well. I think this will make the games a lot more fun and a bit harder.
I think the prices are fairly well priced, in the sense that for Overpowered, it costs you 3 gold for either a(n) Golden Apples or Obisidian, it comes down to you deciding whether it would be smart to invest in buying more Obisidian or Golden Apples. Agreeably, it may be annoying when playing Op-Half and having to fight a player either spamming Golden apples or Notch apple recycling, but that also doesn't mean they're unkillable. In my opinion, I think it would be best if they left the price at 3 gold per apple rather than increasing it, however, regarding the topic of reducing the number of Golden apples in the kit, I totally agree with you on that. Since, you can easily get 4 golden apples right off the bat, by simply jumping off and resetting the kit, but even then 2 golden apples can make a substantial difference in any battles early game.
Side note: Can you add a poll so that people can vote on whether they should change the price of Golden apples, and if they should reduce the number of Golden apples in the kit. Make it so that players are limited to 2 votes that way they can vote on both topics.