I have to say that I was thinking the same as you, 1st of all let's see how "[element] Magic Affinity: Magic Accuracy +" works:
[element] Magic Affinity:
Magic Accuracy +1 =
Magic Accuracy +20
[element] Magic Affinity:
Magic Accuracy +2 =
Magic Accuracy +30
[element] Magic Affinity:
Magic Accuracy +3 =
Magic Accuracy +40
[element] Magic Affinity:
Magic Accuracy +4 =
Magic Accuracy +50
[element] Magic Affinity:
Magic Accuracy +5 =
Magic Accuracy +60
You can also check more info about Magic Affinity here:
http://wiki.ffxiclopedia.org/wiki/Magic_Affinity
Now Let's compare the Magic Accuracy for each stave:
[ Shamshir +1 (sword) ]
MP+60
Magic Accuracy +14
[ Shareeravadi (staff) ] ( Shareeravadi +1 = Mag. Acc. +? )
MP+75
Magic Accuracy +16
[ NQ Staves ]
[element] Magic Affinity: Magic Accuracy +1 =
Magic Accuracy +20
[ HQ Staves ]
[element] Magic Affinity: Magic Accuracy +2 =
Magic Accuracy +30
[ ToM Staves (golden ones) ]
[element] Magic Affinity: Magic Accuracy +4 =
Magic Accuracy +50
[ ToM Staves +1 ]
[element] Magic Affinity: Magic Accuracy +5 =
Magic Accuracy +60
According to this, we can notice that:
- Having a Shareeravadi staff is equal to have a NQ staff -1
You will have less staffs but still need to increase your inventory w/more equipment/accessories to add Mag.Acc/MND/INT
- Having two Shamshir +1 swords is equal to have a HQ staff
Again, this is good if you don't want to swap equipment but still need to sub /NIN, wear 2 swords "always" and increase your inventory w/more equipment/accessories to add Mag.Acc/MND/INT
- Having a ToM stave will increase your Magic Accuracy a LOT
Mixing this w/merits will work well, and "maybe" could use less Mag.Acc/MND/INT equipment/accesories
This is just a comparison to show how "[element] Magic Affinity: Magic Accuracy +" and "Magic Accuracy" works and IMO you don't need to work on all ToM staves, if you're playing as RDM only can use ToM earth/ice/wind Mag.Acc. staves, but if you have RDM/BLM/SMN I have to say that you won't save any inventory space xD
Atm I'm working on/planing the following staves for RDM/BLM/SMN/WHM:
[ WHM/RDM ]
Surya's Staff +1: "Cure" potency +20%
[ BLM ]
Indra's Staff +1: Lightning Affinity:
Magic Damage +5
Varuna's Staff +1: Ice Affinity:
Magic Damage +5
[ RDM ]
Varuna's Staff +1: Ice Affinity:
Magic Accuracy +5
Kubera's staff +1: Earth Affinity:
Magic Accuracy +5
[ SMN ]
Varuna's Staff +1: Ice Affinity:
Avatar perp. cost -6
Vayu's Staff +1: Wind Affinity:
Avatar perp. cost -6
Yama's Staff +1: Dark Affinity:
Avatar perp. cost -6
Shareeravadi +1: INT +8
Pet: Magic Attack Bonus +11
Hope this info can be helpful to you, have a nice day and... GL with your Trials! :D