I think Ultima III Exodus is the more important game, but Avatar is the more polished and certainly does a good job with consequences and altered gameplay based on player input/actions. This was ~1985, too. Exodus might be why people bothered to make Dragon Quest/FF but Avatar is a bit more enjoyable and it's a series that was already doing new and cool things... before other series were even twinkles in their dev's eyes.
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Donny: Are they gonna hurt us, Walter?
Walter: No, Donny. These men are cowards.