Bottom line, he fled before sentencing. You can't do that. The courts probably would've been more lenient had he simply return months ago, like he was asked to, to resolve the matter. The judge was even sympathetic to his case.
If his old judge, who is now dead anyway, was a total nut job, he should have just appealed. If his argument is that he fled out of fear from Judge Rittenband, then he should have turned himself in after the guy died in 1994.
Polanski is obviously afraid of more than a crazy judge.