It's definitely slowed down, in the sense if fewer posts.
It's losing its identity - the distinctive lingo is vanishing, the 'outdated' platform has been tweaked for the sake of being the same across all deceived, which means the things you could see on Active on desktop, like who had posted last on a thread and when, have been removed, taking away a bit of that sense of community, because there's no easy way now to see who's about. And I don't get the idea that because you can't do it on a mobile, it should be gone everywhere.
And of course the amount of trolling is ridiculous, and deleted threads are these days expunged completely sometines - you can't see what happened from your TIO as sometimes they've gone from there too.
MNHQers no longer seem to join in threads from time to time (would we still know who had a crush on which film star?) and seem to exist only to tell us off - sometimes for long-term discussed and approved things for which policy has changed (fair enough) but if no-one tells us we don't know you don't like it any more. That might seem like a petty thing, but it shows a difference in MNHQ towards its content creators, and people don't like being taken for granted and being on the receiving end of uncommunucated changes.
Also, because the levels of trolling us so high, there is a (I think) an expectation that threads are not true. MN was never a safe space (no open Internet site is) but it used to be a place that it was worth taking your problems to. It's nit that any more either.
I'm still here because, despite all that, I still like the place better than many others. But it's a shadow of its former self