W Def and M def after Big Bang?

It has been said it plays a much larger part post BB, but I have yet to see any good short descriptions just how much it will matter. Speaking purely about survivability, how much HP would 1 w def or m def be worth (Pre BB the ratio is pitiful,1 hp>1 def)?

From what I can tell from fiels ever helpful work, the damage reduction by 1 point in wdef/mdef varies by how much attack the monster has, as well as how much defense you have. Generally the more defense you have, the less 1 point of extra wdef makes, since its proportional to the square root of your defense (unless you're considering one of the rarer cases where its a static reduction, at which point you'll have enough defense that survivablity will almost certainly be a non-issue)

Fiel has a calculator here as well as a list of monster attack values to use with it here
Not entirely sure about Mdef/Monster matt values, since not much has been said about them, but they're probably similar

Doing a bit of research, there are about 100 mobs which have higher Magic Attack values than Physical Attack values. Of these, the average increase is less than 100. Many of the outliers are major bosses (Horntail, Pink Bean Statues) for which the required HP value is already known. One of the areas which I did not check are Magic Attack values that are associated with specific attacks. Some attacks have their own magic attack damage that override the default magic attack given to the mob.

In short, if you have enough HP to take touch damage from a mob, chances are very good that you can take a magical hit from it as well.

The known HP to survive bosses will not be as static as pre BB if def plays a bigger role though, hence me asking. To simplify the question a bit: What would be more beneficial, a zombie ring with 100 HP or a Visitor ring with 20 hp and 60 w def and m def? If it matter for the formula, let's assume we have 900 of both without the rings.

Zombie ring with 100 HP.

60 WDEF would only reduce damage by about 15 - 20 flat, and you don't gain +1% reduction until 1024 DEF. So yeah, the 100 HP is better. Also factor in HB if you're bossing.

Also, make sure to check the formula. Sometimes adding WDEF gives you nothing. Like in this case. If you were going to PB and you had to decide whether to bring +100 HP or +60 MDEF/WDEF, the +100 HP winds hands down, no questions asked, everyone go home. The additional WDEF doesn't reduce damage at all.

Zombie ring with 100 HP.

60 WDEF would only reduce damage by about 15 - 20 flat, and you don't gain +1% reduction until 1024 DEF. So yeah, the 100 HP is better. Also factor in HB if you're bossing.

Alright thx Fiel. So def is still kind of inferior then. Not what I had hoped for but one shall cope.

Static defense on equips still doesn't do all that much for you. However, there are skills that give +% defense and your stats also give you defense. It should be pretty easy to break 1000ish defense.

Using my current unbuffed stats as an example:

71 str, 80 dex, 1096 int, 146 luk, 800 wdef, (1952-1096)=856 mdef

(1.2*71+0.5*80+0.5*146+0.4*1096) + 800 = 1436 wdef (-18% damage / -359 damage)
(1.2*1096+0.5*80+0.5*146+0.4*71) + 856 = 2312 mdef (-24% damage / -578 damage)

So yeah, defense on your equips still isn't that big of a deal but defense does play a much bigger role now.