Even if the old way isn’t all that intuitive I’d still prefer using the old color code style over JSON, less stuff to type out and much better for the chat if you are trying to use color code in the chat.
Pls no tag for each and every color. Also, why introduce another way of formatting messages? We already have the &-syntax, we have JSON, adding XML would only create confusion.
We haven’t decided this completely yet, but there will be a way to load colored messages easily from configurations. Because the JSON format is used by Minecraft itself in various areas like command blocks, JSON will be most likely the only way supported directly in the SpongeAPI.
While loading colored messages in the way Bukkit did previously (using color codes) is also possible in the SpongeAPI, this is deprecated already and only designed to be used for converting old configurations or simple usage like coloring sent chat messages by players. It supports only a small part of the features available in Minecraft now (click actions, hover actions, are not possible) therefore JSON should be preferred because it supports all these features.
At the end, every plugin should support the JSON format for messages, however providing additional formats for easier configurations shouldn’t be a big problem.