As an update...I'm relatively content with the situation now that I have gotten the ANCESTRY board cookie to "take" and "stick" -- I've even rebooted and it still is holding. I would prefer to admin my boards on the RootsWeb side mainly because of the colors which make it easier to see visited links vs. new posts, but I can always admin on the RootsWeb side and when I hit a lengthy thread that I want to view in Flat view, newest first, I can always switch over to Ancestry and do that.
I still feel that 10 messages per page and thread view with oldest first is about the stupidest default setting for most users today. The non-functioning cookie would become irrelevant if the default was changed to 50 messages per page (or even 25) with newest first and FLAT mode. Everyone I have chatted with views the boards in that manner (especially admins) and ONLY switch to thread view if they need to verify which post in a thread a reply is attached to. The current default dates back to 2001 when there were still a significant number of dial up users on the board but I'd wager there are very few today.