After reading the full changelog (can be found here: https://help.sketchup.com/en/article/141303 ) I can say there is a lot of change. Some of them (a good share, I may say) are changes that would fit rather in a maintenance release than in a major release, but it is understandable how Trimble may have wanted to bring in front a BIG LIST of changes to impress.
On the other hand, there are some changes that I consider being part of a new release, mostly being related to LayOut and Ruby API. -> Here are a lot of changes, most important ones being that plugin devs now will have the ability to interact with LayOut via code.
Some updates, on the other hand, were pain useless (like filled section cuts), where there is already a fully functional plugin. I don't say that a native integration isn't better, but as long as there are a lot of more urgent issues to fix and obvious problems (like you can't search for a local component using component browser - it will only search in 3d warehouse), maybe the effort would have been better spent on those aspects.
Another questionable improvement would be rectangle draw... which whilst "it may" have its usefulness, the impact of having a fancy modifier when drawing a rectangle is rather small, compared with a better uv-mapping, to say so.
Overall, with the drop of Make version (and the online version not being - apparently - to accept plugins), plus the obvious orientation towards Architects, it seems Trimble's direction to be very clear.
One of the questions that I have now in my mind is if it's really worth for SketchUp to become an architect's tool, where there are already plenty of specialized tools for architects, some of them even better than SketchUp (especially because they are specialized). What was making SketchUp so special was its flexibility and versatility. The flexibility is still there, but less focused on it, less cared about it. Seems it's gonna sink and as another user said "if you don't like it, go to blender" - that came from someone who likes SketchUp to be a "lines drawing tool" and organic or complex modelling should not be part of it - at least that's what I could understand from that statement.
Baseline: SketchUp 2018 came with goods and bads, but seems to be paving the road for more changes (or more promises) - anyway, many of the people who were using the Make version may not benefit anymore of the new incoming features.