There are various people who feel that Lesswrong degraded in the last year. In the same timeframe more and more discussions moved into the open thread model and open threads became weekly instead of monthly.
I suggest to counteract that trend by opening all discussions per default on Discussion instead of opening them in weekly open threads. Having the topics in discussion makes it easy to browse the list of topics and choose the headline that are of interest, even if the thread got opened two weeks ago.
As an empirical matter, it should be possible to track the number of non-Open Thread posts in discussion over time, number of comments on those posts, as well as the number of comments in OTs over time, focusing especially on the region before and after the switch from monthly to weekly OTs. My prediction is that the number of comments in OTs increased as it went from monthly to weekly, and increased again when the Recent Open Threads link was added. Your prediction is that the number of non-OT posts decreased, which seems plausible to me. I am uncertain whether total comments increased or decreased, but suspect they increased.
I think a lot has to do that we at the moment has a rule that certain topics aren't important enough to be in discussion. That's a rule that we could change.