A lil confused about armor(armour,evasion,ES)gear.

Basicly, why would I ever want evasive gear is the question. I look at the armor sets and say to my self, it seems like chain armor would be the best to get no? Provides armor + ES(I like to call it, fake HP). Why would I ever need other types of gear? While it is nice to dodge attacks, but when you don't you are pretty screwed.

ATM, I am playing around with a ranger in chain gear, but in the back of my mind, something is telling me this is not the way to do it. Especially in later difficulties.

Can someone educate me please. Thank you.

This question requires a very complicated answer.

Each defense type has different strengths and different weaknesses. They complement each other in different ways.

For instance, you haven't asked "why would I bother to get block?" - most people get block and like it. This is to illustrate my point. Evasion scales extremely well at low rating values; block scales extremely well at high values of block. At identical percent values (ie 30% block vs 30% evade) evade is strictly better, because you can't be stunned from an evade (a block can stun you). The issue is, at some point you can't make your percent chance to evade go any higher due to diminishing returns.

Evasion: unmatched defensive scaling at low rating values. Can't be stunned when you successfully evade.
Armour: unmatched defensive scaling at extremely high values (so high most people never get there, though). Reduces number of stuns.
Block: extremely good defensive scaling at high percent block; can still be stunned even when blocking.

Now you have to also look at what categories of damage each defense gives you.

You'll also find that armour/ES is more problematic than it sounds.

You just confused me even more and blew my mind at the same time.

If I got this right, what your saying, It is not wrong to go lets say armour/evasion gear if I can cover it's weaknesses.

Also being a "bow" ranger. I don't get block. So what is the early game meta for ranger till I get IR?