I would completely agree that they should adjust the mage relics and mythics to actually be useful to the jobs that wield them, however you did know what you were getting before you bought it. That aside, claustrum is the best DD staff (I was skeptical about this, but it holds up to both Empyrean and Plenitas Virga even considering the better gear you get to wear with Plenitas) and is second to AM3 Nirvana for SMN, but Nirvana is worse if you are not maintaining aftermath.
Also, your argument is fallacious (see: ignorantio elenchi, alternatively if you want to lose a few hours of your life, "appeal to worse problems" on TVTropes). TL;DR just because mages have been kicked in the face for years doesn't mean that someone else can't complain for getting kicked in the shin.
(I've provided multiple suggestions for fixing the mage mythics to be good, these are the best I've come up with:
NotesTupsimati 99 Damage 104 Delay 402
Magic Accuracy +40 Magic Attack Bonus +40
Enhances "Stratagems" V & Augments "Storm"
Weather Affinity: Casting time and recast -25%
Increases magic accuracy and magic damage
Augments Storm causes storm spells to calculate as double weather.
Enhances Stratagems V enhances the effect of each level of Stratagem
I: Forces Conserve MP to proc on Penury/
II: Doubles the effect of Alacrity
III: Removes the MP / casting time penalty on Accession
IV: Cureskin effect to "Rapture" and Magic Critical Hit Rate +50% to Ebullience
V: +25% duration to Perpetuance and Skillchain Bonus effect to Immanence
(A precedent for this type of step by step enhancement exists with Ryunohige)
Weather Affinity: refers to spells cast matching the current weather. "Increases magic accuracy and magic damage" would be equivalent to Affinity+4 on the magian staves. (I set it considerably lower due to the other effects on the weapon).
Notes: A logical improvement over the current Nirvana. Halves Blood Pact recast for obvious reasons.Nirvana 99
Accuracy +40
Avatar Perpetuation cost -8
Reduces "Blood Pact" ability recast delay V
Enhances "Blood Pact" effects V
Avatar: Increases Accuracy, Attack and Magic Attack Bonus
Haste +25%
Enhances "Blood Pact" effects each tear is 5% damage for blood pact rage and 10% duration for enhancing Blood Pact: Wards.
Avatar: Haste+25% on pets is not unheard of (PUP can do it always with Turbo Charger) and the Acc / Attack /MAB for the avatar are +40, +25% and +40 respectively.
Notes: Another easy fix. MAB is replaced by Affinity Magic Damage and this basically replaces all Magian Staves for a BLM, serving a similar pupose as Gjallarhorn for BRD. Elemental seal is further augmented to force a magic crit (allowing you to take advantage of mcrit gear even though mcrit is usually a pathetic stat to worry about).Laevateinn 99
Enhances "Elemental Seal" Effect II
Maximizes "Conserve MP" activation rate.
Elemental Magic Affinity: Magic Accuracy +6 and Magic Damage +6
Decreases Casting time and Recast time -15%
Some of the weapons need a complete redesign though.
This one speaks for itself. It's a testament to RDM melee enthusiasts everywhere with a little bit of magery thrown in. "Increases Attack Speed" is JA haste meant to alleviate being ineligible to receive the benefits of Samba.Murgleis 99
Accuracy +30 Attack +30 Magic Accuracy +60
Enhances "Composure" effect and Enfeebling Magic Potency
Sword Enhancement Spell: Increases Attack Speed, Accuracy, Attack, and Critical Hit Rate