I would like to propose adding a field for Status which would contain a list of set values.

i.e.
Ongoing
Completed
Hiatus
Cancelled

Then wherever a list of series is given you could display a small icon showing the status, and it could be included in the Search fields.

The Status in Country of Origin field could then be renamed Length.

I would presume that the field could be populated automatically in most cases, for those where
it cannot be done automatically a value of Unknown might be used.

A further enhancement would be to refine the Length so that it could be used in searches.
e.g.
Use three fields, one to contain a number, a second to indicate Volume/Chapter, and the
third to indicate the type of the issue (Tankouban/Bunkouban etc)