Hi Jorge,
According to the information I have got, the change was made to be more WPF like.
Regarding the email notifications, then we know of this problem which seems to be a DNN bug. Some users have been able to fix it by clicking the "My Settings" link on the forums, open the tracking/subscription section, and then expand every forum section, except the Aggregated, and make sure to click every subsection in all sections. Then save your settings and finally repeat the process, now unchecking the subsections and save.
Palli