The logic behind the clamor for both a notification centre and Instagram is the same: "it is on the other platforms and we are used to it, so we want it on WP8 too."
It is was the app loving, familiarity seeking horde wants. Both are coming to WP soon, no matter how logically you can explain away the need nit to have either present...
the notification center thing is frustrating because there are those that get it and those that don't. Yes, maybe some people are used to android but I'm not. I love live tiles. But some toasts disappear before you can read them and may have come from an unpinned app (maybe you didn't know it gave toasts. Maybe it's an infrequently used app you don't need pinned. Maybe you forgot to pin it). Some toasts aren't associated with a number on a tile or an indicator that they were there (i.e. Battery sense can toast when battery is low or battery drain detected... Its just a real time message that is only true when it's sent. Skype continually sends toasts when you have even just one unread message, reminding you that something needs your attention, and the tile only reflects one message because that's all there is even if it toasted you 6 times. Words By Post toasts when you have a new message but the tile reflects turn notifications only. Same with Words with Friends.)
We cant cover every scenario. Sometimes tile notifications don't include certain toasts by design. Sometimes it's not feasible to update the tile everytime. Some apps have bugs or were coded poorly. Some devs don't follow design standards. Some apps don't get pinned for various reasons. Still, even if Microsoft auto-pinned every installed app (which kinda defeats the purpose), the same problem would exist with all the other reasons mentioned. I don't care if I have a notification center that tells me I have email when I can clearly see that on my tile. I do care if, while I'm busy and phone is on vibrate, I felt 6 vibrations yet can only find 2. What if all I want to do is find the app sending toasts and uninstall it? I don't even know what app it is if I can't get to the phone in time.
If Microsoft wants to make this toast notification center or whatever a tile with a number for every toast that comes through, or a tile with an icon on it indicating one or more previous toasts, or a tile without any numbers... I would be happy. They could even throw in an indicator for if the toast came from an unpinned app with the option to pin it. And anyone who thinks it is silly and fails to see why some people could really use it are free to leave it unpinned.