Actually being "nice" is absolutely a requirement for a journalist. Being able to use the right tone for each interview and the circumstances in which the interview is taking place is a definite requirement.
Many on here have criticised Reeta Chakrobarti for using the same style to do both hard and fluffy stories. Certain regional presenters attract criticism for trying to "do a Paxman" in every interview when it is often simply not appropriate.
I suspect interviewees will tend to be more open with somebody who comes across as a nice bloke giving them an opportunity to put their side of the story (whilst still challenging any answers where necessary) than they would be with somebody doing a combative Paxo approach.
One can be authoritative whilst still being friendly and warm, as the likes of Simon McCoy demonstrate regularly.
Nicholas Owen is an excellent newsreader with unquestionable journalism credentials and experience as a former ITN correspondent. He's actually underrated if anything - you almost don't notice how good he is. The BBC could have (arguably have) done far worse than using him more extensively to cover for George A's absence. (If only so BBC Midlands can do a "with Nicholas Owen and Nick Owen" anno at 6

)