Yeah, there are also a few unknowns that still need to be adressed. Like planetary collision meshes on the server side, which I explained in another thread a while ago, which is definitely a challenge performance wise.
The good news is that a lot of the basics of the new gameplay already exists in a form or another. It's still far from a complete implementation but there are already some of the required things in place. Team based gameplay for example has been partially implemented since the Kickstarter but was disabled due to the lack of active players to fill the teams. That's why in the current prototype you have players with green indicators and others in red, for example.
Structures already have hit points and could get damaged, but it's also disabled due to most of it being client-sided and having no damaged state assets yet.
The new weapons are already a WIP in the networking tests, as I explained in the past weeks, I've been experimenting with auto-aiming turrets or missiles AI. They don't have special fx or particles ( being a network test ) but the core of the code is ready to be promoted to the main game.
The web infrastructure is already in place, and while there are bugs to fix, it's come a long way already. It still requires incremental patching, a couple of smaller features and a visual skin to look professional, but behind the scenes everything is already working. This had to be done anyways before we could do a release, so we decided early that it was better to solve it in the early stages of the project and let it mature / be stable, rather than implement it at the end right before release and encounter unexpected issues right before release which could cause delays.
Basically, if that wasn't clear yet, our development strategy has been to solve the technical challenges ( with the biggest unknowns, time-wise ) in the first half of the development and to do the easier and lesser time consuming ones ( everything being relative of course, as there can be design challenges too ) in the later half.