Maxwell has alternated between above average and completely terrible his entire career.
If the Seahawks end up moving Lane, it might be a good depth move. But it is worth taking into consideration that the Seahawks really like Griffin, he had some mistakes, but I think he will be a good one. Coleman has played well enough to displace Lane from his nickel position, and the Seahawks will be getting Shead back at some point.
I'm comfortable with our CB depth right now, if the Seahawks move Lane or suffer a serious injury, it would make sense. But barring those two somewhat unlikely outcomes, I don't see the prudence in signing Maxwell.