Seriously, I can't emphasize enough how much I'd like to be able to craft a diving helmet so I can explore/dig/build underwater without having to swim back and forth between air pockets or artificial reed farms.
Will there be things(humans or pigmen or something new) to trade with in the villages?
Will rivers actually flow?
Will villagers get angry(try to kill you, destroy your creations) if you mess with them?
Will villagers build you stuff if you are nice to them?
Do NPC villages have walls around them?
Can you claim land in NPCs?
Are there glass planes?
Is there animal breeding?
Sorry for all the questions, I'm just very excited for 1.8