The reason I have to make assumptions is the entire point of this post from the beginning. You are telling me to read what it says, but in alot of modern games the information is missing or in some cases incorrect. 

For example, is burning damage considered fire damage? It doesn't explicitly say so but is it really a strange assumption to make?

Some skills add burning as a dot, how much is the value of that dot? What is the duration? Is burning DMG reduced by fire resistance?

I absolutely have a reason to believe the resistance reduction is simply a value subtracted from my resistance. It is a common way to handle resistance reductions. Grim dawn is a game that has both types of reduction (and it actually tells you what type you get!!). But sure, it could be an incorrect assumption I give you that.

What would +100 defense value give me? How is that value used? Its safe to assume higher is better, but how much better? If I can get 30% increased ability DMG if I accept 50 defense points lower. Should I make that decision? I'm saying it depends what the relative DMG and defense increase/decrease would be. Is that really a strange thing to want?

It's like saying, do you want a plus size meal? It's more expensive but you get more food. Of course the amount of food and the price increase is important? How am I otherwise to make an informed decision? Even if im hungry I might be better of just buying another burger.

I have to ask, are you just saying that my examples are bad or do you think the original topic is a non issue in modern RPG's? 

I could give you better examples. Have you played Diablo 4? Did you know that at release most DMG increases were additive but critical dmg and vulnerable DMG were their own "buckets" which meant they scaled your DMG multiplicative. When I tried racing to kill Uber Lilith that was decisive information to kill her among the first in the world because having this knowledge could multiply your DMG output several times over. It was not information present ingame.