[Tagging] cliffs and embankents or anything else

[Zecke]

Currently in OSM we have two tags to describe some kind of slope that 
also get rendered in the mapnik chart and a couple of others:
natural=cliff
embankment (in the form man_made=embankment (feature) and embankment=yes 
(attribute))

Is this categorisation sufficient for any type of slope?

There's the question whether "natural" is appropriate as there are also 
man made steep slopes. And there recvently arose the question whether 
the english term "embankment" only covers slopes beside a 
road/railroad/river etc. or a general slope.

The wiki defines embankments as accompanying a line object 
(road/railroad/river). For these the attribute form embankment=* is 
foreseen. However it only defines embankment=yes, ignoring the fact that 
an embankment con be only one-sided (left or right). This kind of 
tagging is also used.

There are cases where one needs to map slopes beside a line object that 
itself is man_made=*. So the slope should be an attribute to the line. 
Would embankment=yes/right/left/both be the correct tag in your opinion?

Regards,
Zecke