Endermen do not go in Boats, Minecarts... I mean what is the difficulty of a game where you can outplay the strongest normal mob by using 5 wooden planks?
Punching blocks with your fist hurts you I think even logs are pretty hard (You can change which blocks and which tools you can use)
Wearing armor in the Nether makes you boil in it It seems to be kinda hot there
Wearing Diamond armor hurts you Ever touched a real diamond? They are pretty sharp!
You stumble sometimes, you might loose your items, it's pretty annoying You don't see how you stumble? That's the reason you stumble!
If you take damage that in Reallife would hurt your leg, you get slowness At least I can't walk for some time if I fell like 10 meter!
A cauldron with water is normally the only way to extinguish fire, now all the water vaporizes in a second so you have to be pretty quick It's so hot there so that 1000 liters water vaporize in like one fifth of a second. Why then not also in a cauldron