I just realized a need I have, and I hope someone would be willing to make a plugin out of it.
The idea: a plugin that creates an event log of all the plugins installed, updates, deleted (Maybe also system upgrades and such).
The purpose: To help one find out what was the "last thing" one did before the blog started doing problems.
The closest thing I found for this is "audit trail". But it's not very detailed with it's logging of the type of admin tinkering performed.