From a usability perspective the implementation of screen in zabbix is really improvable.
Zabbix users in my organisation are often confused of the screen implementation and ui seperation of screens and host screens.
This lowers the user-acceptance of zabbix in a dramatic way

Zabbix should quickly improve the following things:

• The favoure screens perspective in the dashboard should also be capable to use "favourite" host screens
• Slideshows should also capable to use host screens
  (bonus: embed all host screens with a certain name of a hostgroup and switch trough these slides)
• Screens should be capable to integrate "host screens"
• The screens perspective should also provide access to host screens
  (i.e. selectable by HostGroup)