The last major content update was just in December, things take time. Some people seem to be under the impression that just because Red51 updated the Steam Store page to the Unity version that it means the updates should be faster now than before.
The reality is Red51 has been taking an iterative approach to the Unity version development to get it to this point so that it could hopefully increase sales to continue the development. Most of the core mechanic aren't even fully implemented yet and it takes a lot of time to finish those, meld the iterations of them into a seamless mechanic, implement and test it before releasing it. That's not even to mention the near constant deluge of suggestions, fixes, etc. that people are tossing at him to sidetrack things along with his involvement with the community.
We all, myself included, need to keep this in mind more and remember "Rising World" is a marathon, not a sprint. There's nothing wrong with being excited for what's to come next and hoping that at least one of the things we're waiting for is in the next update, but we all need to realize this is going to be a years to go yet process. In a way Red51 has to chase the money so to speak to keep the development going which means some features that might not excite all will take priority over others if it's something that might increase sales. That's just the way it goes with small / indie devs.
He's been busting his ass for years on this game to give us all the best game possible, the least we can do is show some patience.