Up-close melee still feels incredibly frustrating

It also feels clunky because of the collision and monsters pushing you

The only real issue I have after 4 seasons is 2-3 Bosses that have absolutely obnoxious hit boxes. Bone tyrant and the colossal. Both of these bosses are incredibly hard to consistently “hit” with melee attacks. Other than that, melee is fine, and a lot does fall into skill and time learning unfortunately

It feels like being actively punished for playing melee, just look at the Trials, want to get in there and mix it up in a fight? Nope because of the "honour" added in you can only take limited damage as a tank.

As a Tank you can't get hit

And then as you rightly said, you can't get your combos off because you constantly have to run around to safety or go chasing after mobs. GGG have said that they don't want players doing the one big hit, they want long wind up combos (just look at the Oracle), well if that's the case then we need to actually be able to pull off the combos you so desparately want us to use, otherwise we're going to find ways to cheese it

Melee targeting with a controller is pretty janky too. The number of times I’ll disengage from a mob to start chasing down a random single target behind the group I’m targeting is incredibly frustrating.

So far I have played exclusively melee classes. I did a shape shifting druid and a monk and I had fun with both of them

But the first 25 or so levels for monk I did with bow&arrow and it really was just a night and day experience compared to the rest. I'm doing a Huntress right now and the temptation to just breeze through the first half of the game with bow & arrow is so tempting. 

While i somewhat agree, i believe the worst offender in regards to what truly makes melee a pain in poe2 is the 'pushing' mechanic of monsters vs the player. It not only affects game balance, but at times is downright annoying, un-fun and breaks immersion when you are getting interrupted by certain mobs. Players must be able to push monsters in a meaningful way, and what monsters can be pushed and how much you should be able to push them should be determined by character power as well as skill usage.

The defense gradient between being at range and being up close just doesn't meaningfully exist. To my mind, it all comes back to GGG being unwilling to allow people to build serious tank for fear of trivializing their content.

At the end of the day, they'd rather a game where both player and mob can be instagibbed than one where it is feasible to build characters who can play without fear of being one-shot(ish -- e.g. full -> in under a second).

I'm hoping the survivability of melee will be addressed when Duelist is released. We need Fortify and more percentage life nodes on the tree. My only complaint is the collision physics with monsters in melee. It's especially bad in 0.5. I don't remember being shoved around this much by bosses ever and I've played melee every league start.

Even the tankiest build I’ve seen has to sacrifice damage for it. And they still haven’t made ascendencies any easier.

If I were to make changes, I would give each archetype a problem to solve: 

Spellcasters: mana Range attack: accuracy Melee: defenses

In it attack skills would cost very little mana, which would give room to invest other mechanics. Ranged attacks can invest into accuracy, and melee into defenses. Balance through passive point allocation requirements and gear investments.