That's them talking about the incredible amount of grinding required to get dungeon sets (especially with the diminishing returns system), not the progression system itself that caps out at level 80 exotics (and then legendaries, but who cares about those?).
Edit: Seriously, did you read the posts you quoted? Because that doesn't say anything like what you want to imagine they're saying.
Im glad that they are aware that the grinding involved in geting a full set of dungeon gear is absolutely ridiculous. One or two pieces is fine, but what iff you want all 6 plus the weapon? youd be in there until you died
Personally, i love how they are handling gear progression. I grew to hate how WoW did it. Grinding for better and better stats on gear and you looking like everyone else in your class wsnt fun.
Im glad i get the option of going after the gear that i like the best and i dont care if it has a statstical advantage or not.
Their progression -> reward system overall is pretty bad. I know that proper balance needs a shitload of testing, but like I've said before, they give away a lot for almost nothing early on, then they ramp it up so steeply that you are wondering if this is even the same game. They want to discourage grind too, but many rewards are only achieved through grind, so there's a heavy disconnect there.
It will take time, but hopefully it will get there.
I like that the legendaries are the biggest fucking grind known to man. I will never get one, but its nice to see that these will actually be legendary.
Dungeon armor, on the other hand, should not be such an obscene grind.
right now, their system encourages people running the one or two dungeons that they want gear from continously and ignore the rest (i mean, come on, you cant and dont want to run dungeons constantly). that, i think, is a huge mistake. They should encourage people to play as many dungeons as possible since doing so means playing with as many people as possible