AF3 hands => awesome piece for perpetuance, don't think you can skip it
AF3 head => BiS for nuking with Ebullience up (Merlinic might be better...), nice enhancement skill piece and midcast for Regen
AF3 feet => BiS for nuking with Klimaform/weather up (merlinic might be better!)
AF3 body => decent piece for nuking in macc sets, if you have better options you can skip this
AF3 Legs => aside from the stratagem enhancement, this used to be a pretty nice macc piece, but there are better options now.
AF2 body => used to be nice for enhaskill, but personally I use Telchine with enha duration+ now. This is still somewhat nice to fill Sublimation faster. I wouldn't call it a vital piece but it's nice to have
AF2 head => its spellcasting effect goes beyond the FC cap, but I wouldn't really call this item "vital"
AF2 legs => Extends tabula rasa duration by 30 seconds. Arguably you could use the 109 version for that, or even the level 90 augmented dynamis version.
AF2 feet => I use them to increase the amount of +stat you get when using a certain weather (if you have the merits, but why shouldn't you!). Arguably, for this role, you could use the 109 version or the level 90 version. Would still get the same exact +stat bonus.
AF1 head => as AF2 body, not vital but nice piece for filling sublimation faster
AF1 feet => their grimoire spellcasting effect goes beyond the fastcast cap. Still, wouldn't call it "vital"...
tl;dr
get AF3 hands absolutely, get AF3 body/feet/legs/head if you lack better options, get AF2 body and AF1 head if you're interested in maximizing your Sublimation. Can probably skip everything else.