I've had the issue since launch as well, the terrible echo/stutter that happens randomly and yet all the time. During combat, during cutscenes, during loading screens, in residential areas, just all the time. I didn't want to do the MSQ with it going on since it kind of takes the wind out of the cutscenes's sails, so I've been running roulettes with the sound turned off just to be getting some XP.

I've tried changing the listening position, changing the equalizer off standard and back onto standard. I verified the games files, I updated my drivers, my headset is at the lowest bitrate and Hz, I played on DX9, absolutely nothing's worked. When I logged in today it was better when I was just standing around doing gardening for a bit, but after about 15 minutes it started again and I relogged and hopped into a roulette and it started immediately and constantly. Even when I have all the sounds turned off except system sounds, it stutters and lags. The patch didn't really fix anything for me, and the game is still essentially unplayable right now.

The worst part is like you said, we waited a week with nothing whatsoever, then got told to wait 2 weeks while they said they'd fix it, and now the day has come and gone and nothing's changed but there's no feedback. There was never much feedback, and they say they'll keep at it ("We expect sound issues created after the release of Patch 6.0 to be resolved via adjustments to the sound engine.") but it feels like not nearly enough information for a bug with such a big impact that's affecting so many people.