Thinking about it, I suspect that part of the reason they didn't opt to include Vengeance paladins is because they're still working on the oathbreaker flags. There may be flags for Devotion and Ancients oaths seperately, but they're unrefined at the moment, so Larian included them because they're, in their mind, similar enough that if there's a mix up in the oathbreaker flags, it wouldn't lead to something like paladins becoming oathbreakers for showing mercy.
