Hi Yakir Sitbon.
I want to suggest, a capability (for example) called 'view_all_activity_log'. The plugin will show all the log information for users who have view_all_activity_log. If the user doesn't have this capability, it will act as the old way.
The view_all_activity_log capability will allow user to see all activities of all users (every staff).
This new feature I suggest, is very useful. For example, you're building a website for an owner who doesn't know much about technical things. You should disable his ability to manage plugins, change settings, changing themes ... and every thing that may ruin the website. He, because is the owner, he should able to view the activity log of all activities of the staffs. It makes sense, right?