The Enchantment system was reworked using MiriyaShiine's "Enchancement" mod and a customized blacklist. Some Enchantments are simple (e.g. Aerial's Bane: Higher damage against airborne enemies), others - mostly those originating froM Enchancement - are rather complicated.
Durability was also removed.

Worldgeneration was also overhauled. Using Tectonic and Terralith, the overworld is now a lot more vast. The Nether now is amplified and has its own weather, and with Enderscape the End is completely different.
With Katter's Structures, Moog's Series, DnT Series, Hopo's Series and Luki's Series, there are a bunch of new immersive structures and old ones where completely revamped.

All four elements are represented with Earth & Water.
Thanks to a ton of Fuzs mods, blocks like hoppers and anvils now are a lot better, clothes and cosmetics were added, new blocks and missing block variants are here to fill the gaps.
You can now connect chains and leads and even create ziplines.
Thanks to "Inferno", fire now behaves a lot better aswell.
Mob vote loosers return and pillagers have... gotten a small upgrade.
Diversity and a few more mods add feautures you never know you wanted.

Sounds were completely overhauled. Footsteps, rain, etc. are completely unrecognizeable.
Rain now actually looks GOOD.
many things like anvils and snow now have custom particles.
Euphoria Patches ahs been configured to fit the modpack.

With fancy Toasts, advancements now feel a lot more satisfying to achieve.