There is at least one person on HN who likes open floor plans. I know this because I'm that person. When I worked in one, I never found myself distracted by conversations, and most often didn't realize they were happening.
I believe the last role took the biscuit, though....
Open plan with hotdesking and lockers... Primary coloured lockers, so it looked like a poor man's GooglePlex. Where the meagre budget had run out halfway through.
You could never be sure where you would be the next morning, or next to whom (inc. constantly teleconferencing middle managers). There were two banks of desks with dual monitors, supposedly reserved for developers. Sometimes, non-technical personnel would grab them, and not even use the monitors... Just their laptop screens (for Outlook, basically).
That was slightly irksome :-)
But you'd probably go insane in my working environment, which is in a house surrounded by fields miles from a city with no one else in it, except me.
Point is, you should tailor the spaces to the individuals working in them. There is no Generic Industry Standard Employee. Which is why trying to enforce Generic Industry Standard Working Environments is maybe not such an effective way to get cool stuff out the door.
As for Agile etc - it's a 20th century methodology, not a 21st century one.
I have no idea what 21st century software development is going to look like. Nor does anyone else, because no one has invented it yet.