One of the issues with WP7.5 was that the core apps were so integrated into the OS that updating those required a complete OS update. But when it comes to Windows 8 all core metro (windows 8 UI) apps receive updates frequently through windows store. I see that even android uses that same strategy. Is it coming to WP8 too?, did i miss the news, did Microsoft confirm this already?
I don't know if they addressed that exact question. The way I understand it to work is updates will be pushed to your phone like updates to your PC. The only catch is you have to opt in to the process. If you chose not to opt in then the updates have to pass carrier approval before you get them. This should allow MS to update core apps whenever they want.