It's all about the material. LA Confidential is his masterpiece, followed closely by Wonder Boys. 8 Mile is decent, much better than it should have been. But since 8 Mile, he's squandered his Oscar power.
I think it's definitely in his power to make another great film or even a few more. But he seems to have fallen into his good films by accident, judging by the ones that are not as good.
While the material has a lot to do with it, I'd like to defend Hanson and say he's always elevated the material. His early genre thrillers like
Hand The Rocks The Cradle and
The River Wild benefitted from above-average performances. (Even
Bad Influence was the first time I believed Rob Lowe could
Act.
He's also gotten career Best performances from Kim Bassinger, Toby Maguire, (arguably) Michael Douglas, and yes, Steve Guttenberg. He worked really hard with Eminem to make that performance (and many of the untrained supporting cast) very credible as well.
Hanson doesn't have an identifiable visual style, but he's really good with actors, and all his films...all of them (be it
L.A. Confidential or
Lucky You) come out better than the final screenplay would suggest.
Does that make him Great? I say, no. But he's definitely better than average.