Supreme court justice is not a figurehead position, nor a management position, and there are qualities that matter aside from voting yea or nay as one might like.
Can she hold her own in deliberations and cross-examination? Can she write an informed and well-reasoned and legally respectable opinion? Can she stand up to other justices who will put her to the test, and may try to intellectually intimidate her?
The personal connection to Bush and the lack of a 'paper trail' are complicating issues, but less important than competence, in my opinion.
Fortunately the questions of competence and backbone will probably be resolved by the confirmation process.
You are correct that the senate confirmation hearings will be telling ("I cannot respond that question" . . . not withstanding) and I look forward to the light of truth being shone therein.