>>717829810they added very little content. 1.18 just changed the world generation algorithm of the game, similar to the 1.7 update. the actual work of getting the new vertical biome format and raising the world build height was in 1.17, but only custom servers and data packs had access to those features.
1.16 is not really a big update either. They've changed a dimension that hadn't been touched since 2011 with the 1.0 release (excl wither skeletons spawning). The nether now makes the game much easier by allowing players to get new resources while not really increasing the difficulty. The hoglins food farm you can make after 2 hours in singleplayer is really broken, especially if you compare to previous solutions that required tens of hours of spawn proofing (e.g overworld passive mob farming). Pigling trading is too powerful. You only need gold, which the 1.16 version made way easier to find, and you don't even need to leave the nether for that. Before, it took hours to assemble the required ender pearls to get to the nether, now you can pretty easily beat the endergragon after 1-2 hours of gameplay.