Ironically, I've done very little with the new content since 1.7. There is still a good bit of 1.7 and 1.8 I haven't used at all. The potion dynamics seem interesting but I'm not sure if I'll use them. It feels like they're adding all this content to fill out the game's challenge, but then the actual challenge (going to The End and defeating a dragon) doesn't amount to much. Sure, maybe the dragon is super hard to kill. But then what happens in between? I liked Minecraft most when it followed a simple yet clear progression:
1. Start with nothing.
2. Get some wood, make wood tools/shelter.
3. Use wood tools to get stone, make stone tools/better shelter.
4. Use your stone tools and torches to go caving, find iron, gold, and diamonds.
5. Make iron/diamond tools and armor, keep exploring for caves and dungeons.
6. Build yourself up a nice inventory of goods, both manufactured and found. Presumably, in the process you've built a sweet residence, as well.
The Nether had the potential to add a further challenge. You could only mine obsidian with diamond tools, so you had to have reached the limits of crafting already. Problem was, once you got to the Nether, you were presented with a few new block types (none of which are essential) and one powerful new enemy. Why was there no potential for "Nether tools," somehow more powerful/durable than the other types? It just came off very half-baked.
I like that there is more content, but I also get the impression there isn't much of a progression anymore. Once you get diamond tools, then what? Making potions and enchanting things seems more of a lateral move, a sidebar.
I don't know, maybe the final game will be awesome. But from what I've heard about the pre-releases, it appears a bunch of things were added with no attention paid to creating a cohesive experience. Minecraft had a cohesive experience at the end of Alpha, even if it had no actual endgame. What you did to move from one step to the next at least made sense.
Maybe we should take our existing server world, carve out the parts we've built on, and move them to another location. Start over with a new spawn, and see what happens. I wonder if it's possible to run multiple "overworlds" in parallel, using types of portals to go between them? I'd be okay with starting a new world and leaving the old one accessible that way, too.
Even now, I'm tempted to head out into the unknown with just some tools and supplies and set up a new home. But I may not do that until the game reaches release.