@jclements said:

......If there are a series of contiguous segments which are equal in length and their common angles are equal, then it has all the characteristics of an arc or a circle (sum of common angles = 360°). You would think there would be a way to "regenerate" SU's arc or circle.

JClements,
In case of retrieving the arcs information:
What you need is the centre of the ‘arc to be’ which is easy to reconstruct.
(intersection of two lines perpendicular to two segments (not to close))
Also an even number of segments in the ‘arc to be’. When you are one segment short you’ll need to rotate/copy one accurately as an extension to get the even number. Input that number as xs (= number of sides) when you now apply the arc tool on the ‘arc to be’. The result is an arc nicely replacing all the separate segments.