In my mind, slanted deck is a bug. Not because it is unrealistic, but it appears incorrectly in the designer section, therefore unintended by CL.
A brief note on point 2. Unless you build perfectly flat bridge deck, your train will ALWAYS leave the track at some point. You just knocked out 90% of the record bridges and the main advantage of complex mode.
Personally all these rules just make me want to build dirty bridges. Anything goes apart from obvious bugs.