Faolyn
(she/her)
The historic Celtic Druids aren't really relevant to the discussion.
(1e PH)
Are you legitimately saying that you would have two different classes for people who exemplify primal nature and the elements based solely on the fact that one of those groups of people uses four elements and the other uses five?The current Druid construction isn't historical, but it more or less holds together, thematically, because it is at least drawing from traditions that fed into each other a great deal over time. The five-element bases not part of that theme.
Especially when the base class is a complete mashup of an incomplete understanding of an ancient Celtic religion mixed with Greek philosophy? Even if the DM is simply using a different set of elements--since there are many, many different types of elements out there--but isn't basing it on any real culture?