Universally, it's hard to agree on what the Wandering Trader should trade.
I think the Wandering Trader should have trades that change based on the player's xp levels, advancements, or time played in a world. Basically, the trader would offer items that better suit what the player could use at their current state of progression. Saplings, coral blocks, and ice might be good for someone who hasn't explored all the biomes nor has attained proper enchantments yet. Just replace the emeralds with something the new player can easily provide early in-game. Once they have got all that good stuff though, like diamond armor, enchantments, and biome-specific blocks, the Wandering Trader could raise its prices and offer more valuable items like nautilus shells, name tags, invisibility potions, and just maybe even armor trims.
