Recently we used soap to close issue, and forgot to provide resolution, that resulted in UNRESOLVED closed issue, instead of exception that indicates missing resolution.
This is because resolution is not a required field, the view on web page is a hack, misleading.

I found two related issues: JRA-7969 and JRA-10431, seems we may have problems if set resolution to required, but I update it in DB and then test again, not problem in creating issue, and got exception if no resolution using soap. I checked codes, seems we already fixed resolution issue in lower level, i.e. we validate parameters only if field is on that screen.
So I think we need to:
1. Make resolution required by default and can't be optional, same as Summary.
2. Remove hack in view code for resolution.