A lot has changed in LightWave. Here is a curated list in alphabetical order with links to pages that describe the features:
Pages describing features new to LightWave 2019 have the label New and the badge above
Create procedural shapes that can be booleaned live in Layout
Use Empty Volumes for creating procedural volumetric shapes or converting meshes to volumes and vice versa.
The new Interchange bridge brings far more control over FBX assets including takes and animation from multiple FBX files.
Realtime-optimized bone system version for better interchange with Game engines.
Animated sculpting, weight mapping and vertex painting in Layout.
Converting meshes to volumes and vice versa, plus all the other advantages of a VDB workflow open amazing new modeling and animation possibilities
A backdrop shader for creating amazing skies with a new Light Type, simulating a physical sun.
Stepping back changes for more than just transformations in LightWave is now possible. Revert changes made in Dopetrack, the Scene Editors, the Graph Editor, and server panes throughout LightWave.
Realtime content created by Tony Prohl for the VR/AR Industry
Smooth real-time conversion to the Unreal games engine for presentations or game design is now possible.
Shade edges to give an impression of additional rounding geometry without needing to model it, and create shading based on wear and dirt with the Patina node.
Nodes for splitting and combining custom materials to create the surface you want.
Node to allow access to all of LightWave's considerable non-nodal procedural texture collection.
New Despike algorithm to soften images to help cure hotspots.
Massively reduces memory use for images in-scene at render time.
The effect is subtle and best seen full size, limitations of the AnimGIF format notwithstanding
Leverages NVidia graphics card to remove noise from still renders using artificial intelligence.
Newbuffer to extract lighting and shading information from the direct and indirect buffers.
The ability to pull materials apart and build them to your tastes is new to LightWave 2019. There is access to Fresnel Functions, Material Components, Material Integrators, and Material Tools has been updated with new nodes.
New Genoma 2 rig from Studio IKIF+ in Japan.
Industry standard Smoothing Groups have been added for more control over the look of geometry.
Select UV Overlap, Select UV Island and Rotate UV are just some of the tools
New tools and workflows to make Modeler more capable of managing UV maps.
The LightWave documentation now fits on any device you care to use it on.
LightWave now works correctly on screens with resolutions larger than HD (1920x1080) by scaling interface elements for a more readable display.
Use mouse wheel, keyboard, regexp and filtering in LightWave menus.
With ,(comma) you can show all nodes connected upstream, and with .(period) you can show all nodes connected downstream to help unravel complex node networks
New snapping grid and keyboard shortcuts added.