Again, why add extra steps to maintain what was already the default setting? Shouldn't you remember what you've read and what you haven't anyway?
No I can't. Usually, I login and read threads I have posted/subscribed to in UserCP, then I click "New Posts" to show new posts since I last visited (blocking forums I'm not interested in). The problem with the old setting was if I spent ten minutes or so in one thread, I would come back to see all the "new posts" marked as read, so had no way to figure out what was a new post any longer. In 24 hours or so this can be 400-500 new threads. There is no way I am going to remember what is new.
I think the chink here for you is you are not using the "auto-subscribe to threads you post" option. If you do use that, the new settings work really well.
I don't mean to discount your concern. I can see how the way you were using the forums may need to adapt a bit with this settings change.