nope, this makes no sense.
The whole reason why shield only has physical defense normally (and only a bit of magic defense as a secondary option) is because it is designed to block physical attacks,reducing its damage.
The block substat also can help mitigating magic damage by 50% already, and, as you said, the armor also offers magic defense, even on plate and leather armor.
Now what you forget to tell is the following:
- there is the option of blue gems on top & bottom armor to increase magic defense further (2x 8 star blue gem add 3k magic defense)
- upgrading the armor adds as much magic defense as physical defense on top/bottom/gloves/shoes
- there is the infamous Nuaele card to increase basic magic defense when wearing plate armor
- there are Pardoner buffs to increase magic defense
- there are armor enchants from enchant shop to boost magic defense by up to 15% (top/bottom/shield)
- there are enchant jewel options that reduce magic damage taken and a PVP damage reduction which includes magic damage
- accessories only add magic defense (and a lot on high upgrades & transcendence)
On top of this bunch of options, there is also the fact that magic attacks in general are mostly unable to ignore magic defense and to penetrate block.
So while a shields physical defense is ± only worth half in battle ( a lot of damage skills ignore 30-50% physical defense and/or penetrate block), if you add a magic defense option,
the Cleric/Wizard facing you would have trouble going through all of your block, evasion and on top of that even your magic defense that is unjustly boosted even further with the already abundant options to increase magic defense to a level where magic doesn’t threaten you anymore.
You also disregard the huge disadvantage of magic being unable to shorten animation delay and/or casting time, locking the magic user out of combat for a few seconds to prepare an attack.
So, if you wanted to implement shields with magic defense, you’d have to remove all casting time, animation delay and add rooting/disabling effects to all magic circles and channeling attacks for a fair battle environment.
By the way, your suggestion won’t be implemented anyway since the developers acknowledged that because magic damage doesn’t really matter in PVE and PVP, the cloth set is ± abandoned and useless. This is why they are opting to buff magic attacks so people will opt for Cloth armor+shield rather than go full plate&shield instead.
Your suggestion would just result in one thing: making the cloth set completely obsolete,
and that at a time when IMC is planning to add armor attributes for Cleric and Wizard to be locked onto cloth for the most benefits.
Here’s some bonus math for you:
Base mdef at level 390 = 390 mdef
Full +11 T10 Velco plate set = 11548 mdef
Full +11 T10 Drakonas accessory set = 1981 mdef
8 star blue gem on top&bottom armor = 3070 mdef
Pardoners Grace buff = ~ 5%
Nuaele card x 3 = 30%
Enchant Shop x 3 = 15%
Total mdef = 25483
This is without calculating the additional mdef you get from every point invested into CON,
a 500 CON character will have about 3-5k additional mdef (so in total up to 30k mdef without cloth).