Like ZB said, XT cracked the Core, Unlimited blew it apart, and now Classic is drinking its sweet nectar.
To keep the momentum going, I think we need to make it clear that the primary goal is to get that first 1.1 MB block into the Blockchain and decentralize away from Core. How we achieve this goal is secondary.
1. We need to break people out of the "one-implementation-to-rule-them-all" mindset. Implementations can be made compatible (and in fact symbiotic). For example, running Unlimited helps Classic and running Classic helps Unlimited. If people really understand this, then hopefully they migrate away from Core to more than one implementation, in order to split the power and help avoid another developer centralization crisis like the one that occurred with Blockstream.
2. The community needs to understand that there is no way to be 100% sure that the first block > 1 MB will be accepted by the network other than by mining one and seeing if it sticks. This problem is fundamental and would apply even if all the nodes were still running Core. Because of this, online forums should be open and censorship free, nodes should signal their preferences in the user-agent string, and businesses and thought leaders should make clear statements.
Regarding Bitcoin Unlimited development in particular, I think the most important task right now is implementing
BUIP005 (block size limit signalling in the user-agent string). I think the community will be intrigued to watch this data as more and more nodes start to signal their preferences. Many people still seem confused about what "Bitcoin Unlimited" is all about, but I think they'll start to "get it" when they see graphs and tables that summarize the preferences of a bunch of nodes.