Zabbix WEB GUI should perform integrity check when exporting Templates/Hosts/Maps etc. to export only items that can be used (imported) after with guarantee. Let's call it Zabbix Guaranteed item export-import.

Today you can export items with no problems, but you will have a lot of headache to import them in another system, to prevent that, there should be some solution to check integrity of those items when exporting.

There is no point to backup/export items if you can't import them in normal way - without spending several hours editing xml file.