Aditya Mukherjee's post "Things I would love to see in iOS5" has risen to the top of Hacker News. Aditya includes a couple aesthetic upgrades and two that I think are a very big deal:

"Better Push Notifications: Apple should just straight out copy Android’s Cloud-to-Device API. That’s it.

Better Notification System: They hired the fellow who designed WebOS’ notifications, so I’m sure this is definitely coming. Goodness knows we need it."

Notifications are an area that needs innovation: it is a key component of app-engagement ... which in turn makes the app ecosystem more effective / efficient ... and in turn allows consumers to better use / access their content

That said, from a consumer standpoint, notifications can quickly become overwhelming. Work is needed on the customization, management and archiving side as well. Without great thought, my gut says that notifications deserve their own SMS-like core application (by Apple) where notifications by provider are listed and managed just as your SMS history is stored. Search, archiving and room for rich messaging (beyond the limited text) would go a long way to:

- making applications more powerful. Imagine the potential for ESPN's ScoreCenter, Kik, Square and other varied apps.

- gives developers more room for creativity and a better ability to engage users on an ongoing basis.

- gives users better control, history and utility.