[timewizard]

> It doesn't even support multiple administrators.

You can easily create multiple accounts that have the uid 0. Groups are a fundamental part of discretionary access system and several administrative groups exist by default. Your modern desktop oriented distribution may not take advantage of these facts.

> logs say about who performed an activity whenever administrative activity happens?

Simply enable process accounting and setup a program to capture that information. The early BSD distributions had this and had many command line tools to query the information it stored.