Have you ever hired?

No, it's not enough. There are people out there who can talk great talk, and have great resume, but cannot do their actual job for some reason. Maybe they cannot read the code, maybe they cannot write the code, maybe they can write the code but not in the manner that keeps the rest of codebase working... I've had people like that on my team, it was miserable for all of us.

It is essential to see candidate actually write and debug code. It would be even better if we could see how the candidate deals with existing huge codebase, but sadly this kind of thing can't be easily done in a quick interview, and good candidates don't want trial periods.