Thanks Alex, that is possible, to be honest I never went through this in ArcMap. My experience is creating PDF with translucent/transparent layers/objects in Adobe, Corel and other Graphic/Vector software so I thought applying transparency these days to vector objects is standard. But seems it is not that easy to implement it or it is not priority.
Also after next few hours here are some more information which help me to decide what and when to use:
- use "Points" for Width of lines (definitely not Pixels with default value 1) and don't use anything smaller than 0.7 Points - in vector these are too thin comparing to any bitmap result
- in Layout/Options there is part Enhanced Rendering where for raster/bitmap PDF it is important to use Anti-alias for text to get rid of blue/orange aliasing when using OSBM printing
- the same is possible for Map in Options, it makes lines and texts nicely smooth in raster/bitmap PDF but also it can significantly enlarge the file size, in my case even 10x