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Before UA, remember, there were two things that "everyone knew" about Rangers. They were human, and they didn't have a high dexterity. Wait, what? Yes, you heard that right! So in the PHB in 1e, you see that only two races can be Rangers- Humans and Half-Elves. Except that half-elves were restrict to a maximum of level 8 as a Ranger- IF THEY HAVE 18 STRENGTH! If you have a 16 or lower strength (remember how rare the high abilities were back then, and you had all these other minimums), you were limited to level 6. More importantly, and weirdly, the only allowable multiclass for the half-elf with Ranger was ... Cleric/Ranger. (PHB 17, 23). And Clerics had a max level limit of ... 5. While I do not make sweeping generalizations, I never once saw a Half-Elf Cleric Ranger under the AD&D rules.
But in UA, everything changed. First, there was the opening up of the Ranger class to new races (UA 7). Not just Humans and Half-Elves, but ALL ELVES (except, um, Wild ... because they are too forest-y, or something ... eh ...). So you've added in Wood (hehehehehehehe SHUT UP BEAVIS), Valley (gag me with a ... never mind), High (It's 4:20 somewhere), Gray (do Gray elves exist in Greyhawk?), and ... wait for it ... DARK ELVES. That's right, Charlie Murphy, Darkness. The Drow have come to play in the Ranger Domain. Sure, they needed absolutely ABSURD requirements (UA 9), including a minimum 18 strength even to consider the class, but still!
Meanwhile, the Half-Elf had greatly expanded level limits, with the ability to go up to level 15 in Ranger with Monty Haul abilities (19 strength, 19 int, 19 wis, 19 con - seriously, it was like Gygax was begging you to cheat). Moreover, UA now had a rule that you could exceed the level limits by an additional two if you single-classed as a demi-human. (UA 8).
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