Yeah, this is definitely my biggest problem with the game. Once I accidentally saw someone's fully-explored map and learned that's just how valheim maps look, my heart sank. All these tiny little islands with very little meaningful difference between them. Whether I explore island A, B, C, or D, which all have a black forest biome, with some meadows, and a small swamp, is all basically irrelevant, and half the islands I go past are like "yup. More of that. Seen that already."