A few threads recently have given me this idea.
It seems that there are a lot of smaller guilds out there who would benefit from merging, so this should help bring them together.
The leader of any guild with 10 or less members would have access to a few more options:
1. Merge request. This would allow the leader to set merge criteria for language(s), minimum level, min/max number of members (up to 10) and confirming that they may be demoted in a merged group and that guild buffs, donations, and progress made in the current season of Guild Boss battles may all be lost. Once consent is given, the guild will appear in lists for other guilds to merge with. Consent can be withdrawn at any time and will automatically be withdrawn if the guild becomes larger than 10 members.
2. Search for guild. Lists some guilds that both meet the criteria set above, and have criteria set that means you fit their criteria too. Selecting a guild here and confirming the merge will automatically transfer all members from the higher ranked guild to the lower ranked one (this ensuring that nobody can cheat the system to gain an advantage) and demoting the members of the now defunct guild to ordinary members in the newly merged guild.
You would need to consider how (or if) this could be done gracefully while members of the defunct guild were logged in (and potentially fighting their guild boss), and what would happen to the defunct guild donations and buffs at that point (I think they would have to be lost with the guild - again to avoid exploitation of a possible cheat).
Sounds like a fair bit of work now I’ve written it down...