It's going to depend on two things: the stats on our level 80 AF gear (several Mirage pieces were BiS at 70, for example), and what new spells we get.

BLU currently tends to fall into two major stat distributions depending on role: Crit/Det > DH for DPS and SpS/Det > Crit for Tanks/Heals (and sometimes DoT DPS, depending. I remember seeing them being somewhat close).

Looking at Crit/Det > DH, we see from Eden Savage BiS: Head, Hands, Earring, Neck and Wrist.

For SpS/Det > Crit, we'd prolly have the following BiS from Eden Savage: Head, Hands, Legs, Earring, Neck, Wrist, and one Ring.

Granted, this is based solely on ilvl, and depending on how well INT weighs, you might be able to do some lower ilvl BiS (ex. Blade's Tights of Casting are Crit/SpS while Eden are DH/SpS, the latter has more SpS but might be able to be made up with materia and provides useful Crit).