Starting with the good stuff, the material design of the new homepage spec is great. It makes even simple things, like scrolling through the page, seem natural. It fits right in with the modern, simple look that the internet as a whole is moving towards. I love the fact that you were able to include in-game screenshots along with a solid white background in order to make the UI more clean. Another improvement upon the UI is the fact that key words are bolded out in order to make skimming through the page(which is what most visitors will do) a lot easier. In conclusion, the new spec is vibrant, easy to understand/read, and fits in with Terasology's vibe. The old one had a lot of info that was densly packed together and it gave off a dull vibe.
Now, some improvements you could make. In the section for the different types of users, the fun descriptions and images are a great idea, but might want to consider changing "average Joe" to something a bit more optimistic, as it might come off as a little offensive. Remove the question mark at the end of "a developer might want to get started developing Terasology?", and try to change it to something more witty. The fact that Terasology is "like an open-source Minecraft" is a point that helps a lot of potential users understand what the purpose of Terasology is, so I understand that you are attempting to differentiate yourself from Minecraft, but that line is key. Also, a "learn more" or "more info" button next to some of the key points of Terasology would be useful for curious users.
Besides those incrimental improvements, I think the overall look and feel of the spec is a huge leap forward for Terasology, and it's one that is likely to drive the downloads and user base of Terasology.