Rep number has become quite worthless. Recently I've seen quite a few accounts with a 'healthy' rep around 50 milking rewards.
KE is a metric that can be useful too, but it doesn't speak for itself.
A while ago I suggested a 'user health status'; an indicator that would show you a warning when an account didn't comply with the metrics you want to see.
This is quite difficult to implement in the Front Ends (gathering metrics takes time), so I decided to build it into a dashboard: https://friendlymoose5717.github.io/hive-dashboard/
The dashboard also shows engagement, extraction, delegations...
RE: PeakD should add KE ratio near Reputation score when browsing through user content