Thank you for the positive messages about the ‘Salamander thing’ 
In fact, I am rather optimistic this could be implemented in the game for the following reasons 
- Among the various topics about this walling stuff (Optimal Walling, Option for straight walls, Proposed improvement to wall placement, Age of Salamanders, this topic…), this feature seems to get love from the community.
- I do not have access to the code, but I think this feature should be quite straightforward to implement. When a straight wall is not possible, I assume the game is computing the junction point position between the two L-shape segments. In such a case, it could be done just by replacing this part of the algorithm by a function similar to the wall_end_points() defined here (JS section). If it is not the case, it should still be an easy feature to implement (way easier than any pathfinding improvement).
- AoE2 developers seem to take into account posts in this forum, especially if asked a lot by the community (so any help in promoting it is welcome
). They even insisted on it in this video posted last week.
This choice of the mouse wheel is from the feedback I received on this topic, in order to be coherent with the gate rotation. The good news is that the gate rotation control can be tweaked in the options. So, it would most likely be the same here.
Here are some video samples: Hera, T90.
The ‘Salamander thing’ still allows to build the traditional L-shape wall (even two L-shape walls, you can test it in the JavaScript above).
PS: Before this post, I never called this idea the ‘Salamander thing’ (but rather the ‘Optimal Walling’… which was illustrated in the Age of Salamanders scenario about different QoL suggestions). But I am perfectly fine if you call this the ‘Salamander thing’