Some people are force multipliers. They make everyone around them more efficient. BUT people like this are hard to determine with Standard Performance Indicators.
Personal anecdote:
I had to fight tooth and nail to keep a junior coder in my team because "she wasn't performing well". Yes, she didn't commit often and her code quality was average at best. Tasks took longer than average to complete as well.
But what she DID DO was keep the two auteur seat-of-their-pants 10x coders in her team focused and on task, made sure to ask the correct questions and had them document their work. She also took over their customer-facing stuff so the socially awkward 10x pair didn't need to do that.
None of this showed up on standard performance indicators.
Now she's a team lead at the same company, managing the two 10x-ers.
Now I spent my time optimising/running the system of software creation and delivery, being the face and the glue - because hey, that's me.
I worked with an engineer, let's call him Mark, whose 'talent' was to get involved in everyone else's problems during the stand up. When I first joined, he was 6 months late delivering his own project, which was eventually a year late, and that was the reason. He was a drag on the entire team. Rather than stand ups being a way of learning what everyone else was doing and offering help later, it turned it into guarded, cryptic, monosyllabic updates, lasting seconds. He'd spend half an hour at someone's desk after the stand up, trying to get up to speed on 3-6 months in 25 minutes to knock out a 5 minute solution that never worked. He was asked to leave and productivity soared.
"Don't be a Mark" is still a phrase in our company.
It's definitely not true. Very often the root cause of zealotry is simply passion, enthusiasm especially for something new you start to like more and more every day, and at some point you start to have a false conviction - that it could solve all possible problems. Usually, zealots become more reasonable with time.
Now I’m sure for certain roles, highly specialised stuff that isn’t true. But I tend to be hiring for teams building pretty standard stuff, line of business tools, general saas products, etc. For this you just need smart, reasonably experienced people who are easy to get along with and ask decent questions.
I can add a few things:
With interviewing I have decent results just having an open form conversation, looking first for personality and drive and getting an idea of their technical knowledge by seeing how deep they can go (or if they even can go deep into a subject). References from someone competent dominate, mind.