Iron grinders: I haven't been the one in charge of our iron grinders, but based on the availability of iron currently, the process could stand to be a little more expensive (I like the idea of requiring more heads per upgrade -- maybe after the first 4 spawners, require that upgrades be done to all 4 at once?)
The nether: I like the new nether -- it's more dangerous, but there seems to be a problem a conceptual problem with wither skeleton farming, although I'm not sure whether this is a good or bad thing. Custom flora: One of the best aspects of the new rev.
Portals: I think the portal situation this rev is fine. After last rev, I'd be happy with just 2 portals. My suggestion for future revs is -- you don't necessarily have to have the portals symmetrically spaced out, although I completely understand the appeal. Ore distributions: I mine a lot, and I've never had a problem with ore distribution.
MapWorld: Nice idea, but it's only seeing very sparse usage right now. I'm not (and I assume most people won't) take the time to create an actual image to make into a map/frame, so the alternative is to use a program that converts an image into minecraft pixel art. The level of effort it took for me to learn how to do this was surprisingly high, and now I'm no longer interested in using the plot I reserved--although I still would like to take advantage of it before the end of the rev. As it's not currently very popular, I don't see any reason it will be around next rev. Terrain: Terrain is great. Heavily WorldEdited maps tend to be the more memorable ones.
Spawn: Historically, I've always found spawn hard to navigate, but it's usually not the fault of those who created spawn. I like this rev's spawn. The melon situation sucked on the initial first-day rush, but other than that one circumstance, there's no need for a sign to obtain melons (it is PVE after all). . Custom mobs: I like the idea of trying to make PVE more dangerous through unique mobs. Meowington is interesting but annoying since it feels like it takes 5 minutes of repetitive hitting to kill it. But if you don't have any blocks in your inventory, be prepared to run! I think I've come across a Dr. Cuddles because a creeper exploded behind me and took out almost 3/4 of my health while I was wearing mostly P4 diamond armor, but I've otherwise never seen one. I think it would be neat to introduce 5-6 overpowered (in different ways) mobs that all come with a small chance of dropping an awesome item that is mostly novelty and doesn't give the player too much benefit (e.g., Knockback X item)
Has this been changed from previous revs? I've relied in it in the past in its past form, but haven't used it this rev.