I don't know if we have a dedicated area for suggestions to v5.x.x, so I'll just drop this here. If there is a better space for it, feel free to move this, there. Thanks.
I suppose being a builder by trade is why dead space bothers me so much. Whenever I see some, I want to fill it with something to make use of it, otherwise I consider it wasted. I like a degree of balance that creates a symmetry. When the thread sidebar was introduced, this created such a condition that I hope can be rectified with an out of the box installation.
Once you scroll down the page and get past "x" posts, all you are left with is dead space that is just begging to be filled with something. Of course, this is a uniform condition once you get past those "x" posts on the first page, until you get to the last page.
One solution to this would be the ability to have a block become a "sticky" when placed in the sidebar position, that sticks once it comes into the viewport. Additionally, it might be wonderful to have the ability to have a block, that when placed in the sidebar, given the ability to adhere to the bottom of the page and when that comes into the viewport, it would then force the "sticky" block up, and out of the viewport.
It is probable that some might not utilize sidebar blocks in thread, so giving this ability to the topic summary, would make the out of the box installation, in this mode, better by default.
Please don't get me wrong here, I know I can disable the thread sidebar, but I love it so that is not the point of this posting. The point it to make use of the created dead space.
Thank you for your consideration.