Good feedback, I think there is always room for improvements.
From my perspective:
hy scroll bars when a row of dots would be more meaningful: scroll bars imply a smooth scrolling behavior. But there is no smooth scrolling in the plex. It "feels" more like page turning. Therefore I would prefer a row of dots, indicating the number of pages available and the actual position Dragging past the thought area still continues to scroll the thoughts. Because of this I don't think it necessarily corresponds to dots, which would signify going through a subset of thoughts at a time. I think iOS and OS X has spoiled me for smooth scrolling, but yeah, it's not as responsive and it stands out when compared to other apps.
Quote: yes, swiping thoughts themselves is an improvement vs. sliding bars. But why do I have to aim anything at all? Wouldn't it make sense to tap and swipe anywhere in the plex? Just me, but I would find if I tapped somewhere in the plex and thoughts started scrolling I would get confused and would be very careful where I touched to not scroll a list by mistake. The current way, where there is an area to scroll and an indicator that you can do so (the bar) works for me.