Well, the problem with doing away with the checkbox, and using one field to store all of the reasons for the issue is that you lose the ability to search for one or a combination of issues.
If you want to have just one field for reports, try adding a field to the recordsouce of your report like so:
Issues: Mid(IIf([Training?]=True,"; Training","") & IIf([Technical?]=True,"; Technical","") & IIf([User?]=True,"; User","") & IIf([System?]=True,"; System",""),3)
Of course, replace the text in brackets [] with your field names, and replace the text in quotes with the name of the issue you want displayed. Add as many IIF statemets as you have fields.