Guild Wars and the /guildwar command were fun and very much part of the classic experience on non-pvp servers back in the day.
That being said, you asked for thoughts on a specific idea, and mine would be that flagging specific guilds to be pvp towards each other would be a step towards customizing the server in a designer fashion, and was not part of the original classic experience.
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 --Lumbo - Gnome Enchanter |