If Mash, as a beta tester, gives it a solid 9/10, I think we can expect something decent 😉
I've lost contact with the MAXON team since 2018. I have no inside information about the recent development but I like to speculate. It's fun.
So here's my hypothetical list of "new" features and updates:
1. RENDERING : Something will happen in the rendering department. Cinema 4D's render engines are outdated. The Physical renderer was not seriously developed since 2014. The "external" alternatives proposed by MAXON since then were either mediocre (ProRender) or not fully integrated (RedShift). A new solution will appear. It will be an integrated version of Redshift or a brand new renderer.
2. PARTICLES : I expect a nodal particle engine to replace the old Thinking Particles. This year we celebrate it's 20iest anniversary ! I don't see how MAXON could rely on the expensive X-Particles for any longer. A powerful particle engine is an indispensable tool, it should be included in every modern 2D/3D CG software.
3. DYNAMICS : A new system will appear. It will replace the previous one based on Bullet engine. I don't expect a high end system like Houdini, but the foundation of a new powerful set of tools. It might use the same approach as Mograph, with effectors and fields.
4. SAMPLING / PHOTOGRAMETRY / MOTION CAPTURE: Assets creation is now all about sampling the world - capturing geometries, textures and motions. I predict that Cinema 4D S26 will include solutions for this.
5. VOXELS : Handling complex geometries (generated by photogrammetry, fluid simulations, particles, sculpting, volumes, etc...) requires a reliable grain/voxel system. I hope to see one in S26. I also wish for direct voxel rendering, without the need to generate polygonal data.
6. 3D PAINTING : Not sure about this one, but anyways... I hope MAXON will improve and simplify the texture painting tools.
7. PRIMITIVES : A lot could be done to improve the primitives generators - more shapes, more controllers, more HUD tools, recursive / fractal structures, etc...
That's about it.