In Renewal, the Attack Power(ATK) is divided into two, StatusATK and WeaponATK. In essence, they both contribute to the final damage (StatusATK being multiplied by two).
However, when amplified by racial/size/elemental bonuses (such as Hydra Card or Skeleton Worker Card), only the WeaponATK is amplified.
This makes it so that people no longer rely on 4-slotted starter weapons (such as a Quad-Racial Composite Bow), and instead will strive to get higher level weapons with higher ATKs and Refine rates to deal better damage.
As with ATK, Magical Attack Power(MATK) is also divided into two, StatusMATK and WeaponMATK.
With the introduction of this update, many weapons now possess a flat MATK number (e.g. 280 MATK from Staff of Destruction; 105 MATK from Bazerald).
In MATK's case, WeaponMATK makes up the greater percentage of the final damage, due to the variance factor which relates to weapon level.
DEF/MDEF
Cast Time
The Defense(DEF) and Magical Defense(MDEF) system was revamped in the Renewal Update.
HardDEF/MDEF is no longer limited into a 1-100 point system, with 100 being full immunity. Instead, the effect of HardDEF/MDEF is now reduced exponentially as the number goes up (i.e. the higher the number, the less effect every single point adds); and in DEF's case, the number often goes way beyond 100.
For example, 200 HardDEF gives about 25% damage reduction, and 400 HardDEF gives about 40% damage reduction.
As for MDEF, 20 HardMDEF gives about 15% damage reduction, and 40 HardMDEF gives about 25% damage reduction.
With this change, many armor have had their DEF number raised significantly (e.g. 85 DEF from Meteo Plate Armor; 16 DEF from Naght Sieger's Flame Manteau; 120 DEF from Sacred Mission) to match the new DEF calculation system.