Here's my perspective: I don't think volume makes good terrain. I think good terrain is defined by negative space. The stuff that really seems to get people excited is not large, necessarily -- it is shot through with holes, arches, and tunnels, and has an interesting shape eroded by the algorithm. Unless they've dramatically improved World Painter since the last time I experimented with it, you can't paint space. All you can do is fill it.
Is there still an updated and functioning server mod that can get us terrain like we had in Rev 1?
If I have one complaint about the current rev, it's that building your house on top of a 200+ block-high mountain seems like a great idea until you realize you have to drill down 100 blocks just to find coal or natural caverns. The game doesn't propagate anything above height 127, so if you paint tons of rock and dirt over the pregenerated terrain, all it adds to the game are a lot of double chests full of cobblestone.
Let's keep it interesting, not big.