I still use the Avatar Perp Magian Staffs (sure its a lot of work) but outside of the cost of Geodes (most are fairly cheap these days) they're free. Of course Skirmish staff and the JSE are much better options these days, but with the 99 Magian Staffs (macro in others for BPs), you only need the Reforged AF Feet and Caller's Doublet +2 will cap Perp Cost (-15) freeing up other slots for things like Glyphic Bracers/AF Reforge Pans/AF2 Reforge Pants and so on
Sure it frees up other slots but you end up losing out since you would need to make one for each avatar. That and any summoner worth their salt will be using all of their avatars to be applying various buffs to the party which a specific magian staff doesn't help.
The Evokers ring is one of like 2 rings that benifit summoners via skill, it is still worth getting and the staff can be obtained with minimal work. Just go farm dynamis twice and sell the currency and you'll have enough to buy the items needed.
Also I'm aware that the later stages of the staves are easy to upgrade but the problem is the earlier stages...
50 experience-yielding monsters of the spider family. weather counts as x5 a kill
50 experience-yielding monsters of any family. weather counts as x5 a kill
75 plantoid-type creatures. weather counts as x5 a kill
150 undead-type creatures.
200 monsters of the sheep family.
200 monsters of the rabbit family.
250 monsters of the mandragora family.
250 monsters of the coeurl family.
Then you need the geodes ect after the coeurls. That is a lot of work for just one when you could do them all and be done with it.