That thread was difficult for even me to read through. There's some actual good discussion of trinity and non-trinity mechanics, the good and bad, but then there's a whole lot of bads who need to L2P. If you're basing your opinion off of Yanger or anything of the like, you're taking a fat L. It's the equivalent to trusting the view on Raiding from someone who has never downed a raid boss. A whole lotta L2P, but it's a L2P specific to MMO players who don't realize how limited their old systems had been.
I think I told you a long time ago that players struggle with GW2 because they approach it according to framework of a traditional holy trinity MMO like WoW. When that approach doesn't work and they get their asses handed to them, they shout chaos and zerg without ever bothering to learn a new system. Hint" If the company is saying they're throwing out the old system, then it probably means you need to learn a new system. I didn't have any big problem adapting and understanding GW2's combat, but then I already realized I would have to learn new things. I don't engage games at shallow levels either, so I push myself constantly. I also didn't grow up playing only MMOs and standand fare RPGs. People coming from TF2 or Zelda seem to adapt better to the game and struggle less with the concepts. People who have had tab-target MMOs basically do half of their work in the background while using a Macro button while following Deadly Boss Mod instructions tend to struggle.
Nearly everyone in that thread frames the discussion within Holy Trinity MMO 2.0ish concepts. Not old sandboxy stuff like SWG or UO, or even things like Asheron's Call. And certainly not within the framework of GW2. The most telling thing about that debate is that both pro and con arguments focus on instanced PVE dungeons. Doing so makes sense with WoW. Blizzard stats all their endgame gear around the three trinity roles. Your talent trees are based upon the three trinity roles. So how you build your character is based upon the trinity. Now the trinity doesn't help you with leveling content much, and it's not fully there in PVP, but the trinity is everything to instanced PVE encounters. So t's natural to judge combat and group combat based upon instanced PVE encounters when the game puts so much attention upon those things.
But GW2 doesn't do that. There's many, many ways to trait your character and build your character. There's many Rune sets and Stat combos for every class in the game. Not all of them are good ideas or really viable, but there's not much restriction. The game doesn't say "GO DO DUNGEON BUILD". The content updates aren't all "the next dungeon". Instead, they are a mix of Open World, PVP, WvWvW, and instanced content. And I think if you really looked at their focus, much of it is on open world content for PVE. There's all this interesting PVE stuff that the game has done with Invasions, the Tower of Nightmare, Super Adventure Box, Bazaar of the Four Winds, and Lion's Arch rescue... that nobody is discussing because it doesn't fall under the holy trinity raid paradigm.
There's one note on complaints of chaotic: There's also the fog of war the game has in large scale fights. You can learn it and parse it. I think they could still improve certain boss attack animations, but they have actually improved their tell system and aoe telegraphs. The main issue is the massive amount of skill effects going off is a lot to process. It's a skill check of sorts. The game also uses spatial reasoning and terrain more than MMO-centric players are used to and that tends to give them problems.
It is very chaotic at first, but so will be any new experience you haven't been guided through. The game doesn't guide you through it though. I like that personally. GW2 is rather anti-hand-holding. It needs some tutorials on how combo fields work and how boons and beneficial effects are shared, but it doesn't need more hand holding. Basically, you do an intro sequence and then are plopped into the world without a quest (!) NPC, without a quest arrow, and instead you get an open world designed to be explored.
But the "focus on early dungeon content" issue is the general issue that everyone in that thread is having. I bring a healing Ele to the Guild Mission Karka Rush and to Guild Rushes. Why? Because it helps the encounter. I brought it to Nightmare Tower and it helped. I suggested for Eles to run Water and drop Water fields when I would run Tower climbs. This is overlooked because people turn their brain off in the open world because they turned their brain off while leveling in LOTRO or WoW or whatever. You can't process the combat when you're ignoring the majority of its use.