Nebux have you ever considered making a topic in the screenshot section showing all of the stuff you've built in your world? I think it would be neat to see all of your creations without searching through hundreds of posts to find the pictures.
from my experience i always grab diamond pick at stage 3 just to make an enchanting table, but at stage 4 i make all diamond tools that i need with total disregard of the one item rule. i'm playing Sp always and i like to make big buildings so that is needed for me.
trading with villagers should be limited to the items that you can make in that stage. you can trade with farmers and butchers at any stage, blacksmiths from level 3 etc.
also some redstone use in lower levels is good. you should be able to make a compass and clock at level 3. those are very good for moving around
Wait what? You'r stopping? Darn shame, that's what that is... Will we be seeing any other building-stuff from you on your channel? Would love that!
now i'm in rage quit mode and i'll have a month of very hard work something about 12-16 hours a day at theater. i'll wait until 1.3 comes out and make maybe another world or if i can mod myself the game so monsters can't spawn on upper half slabs. to remake all my buildings is too hard and i don't want to do it. i don't like the mojang team is just add more items to the game but fix the bugs very slow.
this new stupid thing that monsters can spawn on upper half slabs is too annoying for me to continue the project. i have invested lots of tome and buildings in my world just to see them full of mobs and torches.
regards and best wishes!