I know about Oak Sets effect. Yours is already at lvl 40, which is 12% each. The additional 10 level will add 3% for each piece and less than 10 flat for the hat.
27 MDef is additional 41 MDef in battle or 61.5 Atk max. To reach 1k atk on Luna you need much more than that, hence why I said Luna needs good enchant. Normal DPS unit needs to roll good enchant mainly on weapon and accessory. Luna needs good roll on armor, hat and accessory.
In all my posts, I've never said good enchants are not important, but I don't place particular emphasis on good enchants because other physical dps also need good enchants to hit 1k. Conditions are all the same, but Luna has an easier time.
And I am not sure why u said 'normal dps need to roll good enchant mainly on wep and accessory. Luna needs good roll on armor, hat and accessory.' Stat increase for enchants can happen at any equipment piece.
Let me explain why. Calculations time!
Physical dps like Cherie:
118 atk (SSR axes like peacemaker give the highest base attack.)
+ 75 atk (Attack enhancement SSR accessories like winged shineguards)
x 1.18 (Max * axe+ accessories = 18% atk bonus)
= 227.74 atk
Many physical dps do not have passives that directly adds attack (altemuller is one exception that I can think of), but their passive mainly add damage. Luna's passive adds mdef directly.
Bow Luna:
Oak armor do not give base mdef
38 mdef (Oak hat)
48 mdef (Veil of light)
x 1.38 (Max * oak set and veil of light gives 38% mdef bonus)
x 1.5 (Wind spiral bonus)
x 1.13 (13% mdef passive from 4* Luna)
x 1.1 (Faction buff mdef bonus at 10%. I'll explain why later)
= 221.27 atk
All faction buff gives 20% to all stats except mdef, which is at 30%. This gives 10% extra mdef advantage to mdef based attacker like Luna.
As you can see, Bow Luna comes very close to physical attackers with the best wep. And she don't even need an ssr wep to hit this.
Flyer Luna is even more extreme:
Oak armor do not give base mdef
38 mdef (Oak hat)
48 mdef (Veil of light)
x 1.38 (Max * oak set and veil of light gives 38% mdef bonus)
x 1.5 (Wind spiral bonus)
x 1.13 (13% mdef passive from 4* Luna)
x 1.1 (Faction buff mdef bonus at 10%.)
x 1.15 (BIS spear - Cursed spear for flyer Luna. Adds 15% mdef at max *. SR Barrier spear also adds mdef)
= 254.47 atk
All chars need good enchantments to hit 1k attack, not just Luna. These calculations are made with all things being equal, and Luna enjoy exclusive bonuses due to her being a mdef based attacker.
Of course, other things like char base stats, bonds, etc needs to be taken in consideration but let's not dig deeper. Remember every mdef point/% Luna gets from other sources are multiplied by her 1.5 windspiral bonus and 10% extra mdef faction buff.
I am not saying Luna > other dps. But in terms of driving atk stats, Luna is easier.