Ok, now I understand why this feature isn’t implemented by default: you just didn’t experienced it as user.
In some major forum software like Simplemachines, PHPBB and VBulletin too, this is the normal behavior: you click on thread title and go automatically to the first post that didn’t read, indipendently if there are other methods to see unread posts or threads and I can assure you that this is very comfy.
Not all user have organized mind and rely on list of unread posts, many of them simply browse between topics and click on title that, for some motivation, awakes their attention and, doing that, if they already partially read that topic in the past, the better experience of use it’s to be addressed to the first unread post, not the first, not the last one.
So I want to ask you, if I take off the topics update dropdown menus (to make interface cleaner, for example) how can I reach the last unread post?
As there is a customized list for each user that shows which are the topics that user didn’t read, it means that somewhere it’s already memorized this information, right? so, should be so difficult to connect it to thread’s title?
Anyway, if it’s so difficult, I don’t want waste your time, this is a really comfy feature but you are not obliged to add it, of course.
I think that SP it’s a good forum, I insisted with client to switch to it, loosing many material of previous SMF one, like attachments, shortcodes and so on, because I rely on it and on your support, but there are some little refines that could make it even better and I advice which ones, IMHO.
In WP panorama SP it’s the best, other forums are not forum but Bulletin Boards, like BBpress, nothing to compare, but all is perfectible 
Thanks a lot for your time
Marco