We got an update a coupla days ago on January 14th that was supposed to improve the experience in rides with large numbers of riders; greater than 1000 or so. We were told this was due to a bug in the app and they exterminated the bug with this update. I cannot comment on how much or how little it has improved the big group experience but I can tell you it has made busy world free ride experience somewhat less than optimal.
During free rides in Watopia today with lots of riders on the road there are more riders doing weird stuff: Flying off the road, riding waist deep in the road, the entire field disappearing, suddenly riding against traffic, etc. The other thing and I think this is a direct issue with the “Bug Extermination”, oncoming fields of riders will suddenly appear when you had empty road seconds before. This makes for a rather jarring viewing experience. Hope you guys can return Zwift to some kind of normalcy and still support the huge ride/race fields.