I have never used the action centre for anything except the quick toggle buttons. The notifications in the action centre are, to at least 90%, useless redundancy. The only time notifications in the action centre are not redundant is when they include notifications for tiles that I have not pinned to the start screen or toasts that I missed.
Well, live tiles update in 30 minute intervals (or less frequently), or in real time if the developer uses MS' push notification service. Live tiles do update in real time if that is how the developer built the app, but that isn't always necessary. There isn't really much point to a weather app updating itself in real time by half a degree. Every half hour is fine, yet I very much appreciate seeing the weekly forecast on my start screen without having to click anything. The same applies to Nokia Drive, which automatically shows me traffic on my commute route before I leave for work.
To me it seems you're sacrificing WP's "glancability" concepts without providing anything in return.