Armour/Life on melee chars

So, I have 25k armor, 2.6k life, 78% ele res, 38k armor applies to elemental dmg, 75% chaos res, 25k armor applies to chaos dmg, 50% block chance.

Yet, I still get assblasted defensewise in many of the pinnacle/boss encounters. I just did Xesht on t2 and between him permaspamming the ice and electricity summons, the arms slamming down and the hand trying to hit me, and his shots, I find myself running around in circles for 90% of the time to avoid getting slaughtered.

The arms slamming down smash me for 80% of my health, the hand just instagibs me, the electricity takes a good 70% out of me, the fireball does also a good 80%, the shot he fires a good 60%, and the ice needs to be avoid to not set me up for death.

At what point do I as a melee get to deal damage? I hop in, break his armour, set him up for a heavy stun, aaaaand I have to run again. By the time I have the next window of opportunity the stun meter is down again and the armour isn't broken anymore.
If I am ranged I can kite it and consistently put out damage, damage that is higher than melee does, and all while the defensive layer of ES provides even better protection against the nukes he dishes out.

The experience is very similar for other bosses/pinnacles. As melee you spend more time with damage avoidance than you do with actually fighting and dealing damage.

So what gives? Either you must give melee the defensive capabilities to, you know, tank damage for a while and deal damage through it, or you must scale up the damage so that the windows of opportunities can be exploited properly.
I like the combo play. Leap slam in, do 2 swings to armour break, boneshatter, warcry and a couple autos, etc. - I just don't get a chance to properly do any of that because I get smashed for 60%-100% of my health with every single attack despite like 5+ defensive layers.