It's a typical "vanilla-plus" style pack, aiming for a recognisable, immersive Minecraft experience with a friendlier interface and a few balanced additions.
There are more early-game survival options - you can make armour, buckets and shears from clay, which generates more commonly than in vanilla. Leather can be made by crafting five rotten flesh in an "X" shape and smelting the result - so long as you don't mind wearing bits of zombie! The Uncrafting Table and Furnus' grinder "Pulvus" give you more options to craft needed materials, like string from wool, or nuggets from mobs' armour drops. The Wearable Backpack is like a pauper's enderchest - you can only carry one, instead of munchkinned nested backpacks. If you're playing with friends, they can actually reach in and grab stuff while you're wearing it! It'll try to place itself safely if you die, but no guarantees if you go lava-diving...
Antique Atlas, Guide Book and The One Probe are in-world counterparts to the usual JourneyMap/JEI/WAILA combo, hopefully helping to retain immersion and suspension of disbelief.
There's a bunch of UX Tweaks: your clock and compass will display to the right of your hotbar so long as they're in your inventory; your armour (yes, I'm English) and off-hand slots are normally visible when you use crafting devices; in general, interacting with inventories and devices is smoother, faster and more flexible. The pack also includes the Faithful Vanilla resource pack and some addons to increase graphical quality while remaining suitable for lower-end PCs, and keeping the original style.
While there's no new mobs, to balance out all the easy-mode filth above, creepers are sneakier and slightly 'splodier, and other hostile mobs will sometimes be tougher. Tameable mobs get extra health to help deal with the increased incoming damage.
I appreciate any feedback you're happy to give, please open an issue if it's a specific request or problem.
The "core" mods are;
Quark
Ceramics
Furnus
Uncrafting Table
Disenchanter
Antique Atlas
Guide Book
The One Probe
Wearable Backpacks