Feinberg's brief was well done and to the point. But, by far, the most critical document with respect to the likelihood of a rehearing is Olson's brief.
In that brief, he laid out two grounds for rehearing. First, the appellate hearing was not an appeal before a neutral arbitrator, but the continuation of a biased investigation. I like this ground, and I think it is the one the Judges will consider. But it is not really different, in substance, from arguments that were made before and considered by the panel, although it is framed differently. On this point, Parker and Chin said:
We see nothing in the CBA that suggests that the Commissioner was barred from concluding, based on information generated during the hearing, that Brady’s conduct was more serious than was initially believed.
They also go on to say that there was enough in the Wells Report about memorabilia-for-deflation and noncooperation that, under the deferential Garvey standard, Goodell could have reached the more severe conclusions he reached in the ruling.
I think the bolded part above can be refuted fairly easily, but I would worry (a lot) about the other judges accepting the second rationale.
The second ground for rehearing is a technical contract interpretation point which I don't believe the judges will find compelling.