Rocker26a
Explorer
It could be done.
But much like in 2e and 3e when it was attempted, you'd have to trade out some many features and elements to have a worthwhile experience that it would much easier to make a new class called something else.
Must say I'm not entirely opposed to that, that's more or less what I'm doing with my current Ranger homebrew tinkerings anyway. The only thing I've held over so far besides the general template is Feral Senses. Though I like them getting it earlier and, it also just being a bit better.
Part of the reason why you might be having an issue finding the distinction between the Druid, Ranger,and Barbarian is because you have a preference of them being almost the same and disagree with the default lore around them in the edition. If youwant them to have the same features you will have issues finding the differences between them.
Might be right, I just think a lot of what exists in that regard right now, particularly for Ranger anyway, is either pretty barebones, or lacklustre, or useless.
That said, I don't think I'd want them to share exactly the same features. Outside of spell crossover I guess. I don't know. I'm trying to keep actual features out of my mind for this, makes it easier to conceptualize the lore/flavour stuff without being bogged down by actual mechanics. In theory anyway.