Early game tools;
No log punching. You can acquire sticks, and then poke gravel for flints. (consider a rarer drop from dirt/grass?)
Use flint to chisel a worktable from a log. (thank you Flowerchild for the workstump concept)
First tools are flint tools- NO stone or wood tools of any kind!
Explosions can shatter cobble/stone into gravel.
Harder gamemode for the pack.
Randomise respawn Upon death, player respawns at a random location. Regardless of when/if a bed was last used. Death still sets time to dawn
Ramp up mob difficulty. Aim to tweak behavior/make "smarter" not just up the HP and attack power.
Don't go overly crazy with changing recipes from standard game mode. Mostly a survival themed expansion