Eldritch Battery vs Chaos Inoculation vs Pain Attunement

While there have been several well reasoned posts about the weakness of Eldritch Battery, there is one thing that prevents us from making it better.

By far the most abusive, overpowered character we have ever seen used Eldritch Battery (and no other keystone would have worked for what the build needed).

The person with that character (actually they built it twice, in different release versions), never shared their secret, and its not that easy a build to get right.

Thanks for the feedback on the three Keystones in the original post.

I am tempted to remove posts derailing the discussion (I may be at fault there either).

Those who don't value Eldritch Battery - what would make it worthwhile?