2, as you listed, they have gotten better at the games that they are playing, and their production style that they make their videos in is probably similar to the way that they did their videos when everyone was bad at the games that they played, and because they are now more experienced at the games, the way that the videos are put together doesn’t work well with the events that happen during the recording.
1: from what I know, not everyone is in the office together when recording an episode because of the quarantine, so that could possibly affect the group “mojo”. I think that several factors have changed the outcome of a video. I think if the poll had options between all of their series, old and new, the results would be in favour of the old videos over the new ones.