- Slide Through of Demension (No portal to another world BS. You dig all the way down, you pass bedrock and reach The Nether.) (You fly up high past the clouds, you eventually reach The Sky Demension.
The problem with this is that when you don't need portals, there are no challenges to get to the different dimension. You could mine all the way down with your bare hands if you wanted to. And you could build blocks up to the sky dimension easily as well.
I have thought of a solution though. Since the nether requires you to mine obsidian, make obsidian a tool type. It would be able to break through bedrock and it would have the durability of an stone pick and the capability of a iron pickaxe.
As for going into the sky dimension, maybe you would have to craft some sort of breathing apparatus since you're going into higher altitude. If you don't bring one, the its like being underwater with the breath meter stuff. Not the best idea since then you can't wear a helmet, but maybe you could also use a potion of breath or something as well.