Simutrans is not an easy game to master. And by master, I mean "using japanese addons properly without getting a headache". To achieve certain visuals, it gets more complicated and in cases more restrictive.
For example: It's easy enough to build normal tracks. But then, there are tracks which 'connect' to one side or both, so parallel tracks would use one bed of gravel. Looks fancy, but currently requires 4 different tracks being used in a particular way, and 'disables' map rotation. That's probably not something a new player would want to deal with when struggling to build their first functional line, and I can't think of any pakset which features those kinds of tracks by itself.
Another example: Curved roofs over stations spanning over two tracks. These are more complicated and more restrictive than common stations, since you are required to build them in the correct order (otherwise, they face away from each other) and you can only use them if there is an even number of tracks. Those are much easier than the track example though, and indeed, they are relatively common in paksets.
I wonder how complicated stuff in a base pakset can get without harming the expierience for new players, and which methods could be used to mitigate their effect without outright removing them.
Getting back to curved roof stations, those are usually in later eras - the player would not have access to them at the beginning of a timeline game and would first learn with easier stations where building order does not matter at all. Perhaps even with double-sided goods stations before using one-sided pax stations, and since they are not THAT complicated, this might be enough for a learning curve.
Another possibility are submenus for more advanced stuff, seperating it so new players don't encounter it, while advanced players could still use it.
What do you think? Should anything advanced be removed from base paksets and offered as addons, or what could be done to keep it in without disturbing new players? Especially newer players: How was it for you to discover game mechanics, what were hickups that could be prevented?