iOS 8 gave developers the opportunity to expand their app to new places in iOS with sharing sheets actions and widgets. It allows for an easier integration with other apps and third party cloud storage providers, and with Healthkit it tries to pull all fitness information together in one place.
A few weeks after iOS 8's release most apps on my iPhone are upgraded to fix bugs and to scale nicely to the new screen sizes. A couple notable exceptions are Pocket, Facebook, Editorial and Unread, but the other apps I use are mostly there.
I'm still waiting for a few features though that aren't available in any apps for the moment, that should be possible with iOS 8's new bells and whistles.
(Not available is an euphemism for: I couldn't find any).
Text Editor with iCloud Drive integration
Byword and Editorial are my current writing apps of choice, but neither of them has integration with either iCloud Drive or the new Document Picker. Since I move from iPad to Mac to iPhone to write, being able to access text files on (any) platform with easy syncing without creating multiple duplicates would be great. But so far I haven't found a good writing app with Markdown support that integrates these new document features.
The new photo extensions in iOS 8 allow users to edit photos from right within the photos app. No exporting, no duplicates, just straight on editing of the original file.
I've got a couple of photo extensions installed already, but those are either apps that allow me to improve the photo (exposure, shadows, contrast,..) or are apps that add some text and effects to an image.
What I'm looking for is Bugshot or Skitch as a photo extension. This would make the flow of taking a screenshot, adding an arrow to show a certain bug and sharing it to someone so much easier.
I half expected it to be a native feature of iOS because Apple added a Markup extension to OS X. But apparently it didn't.
It's something I do daily, and according to this Xkcd chart it's something useful to improve.
Caffeine and Health
I drink a lot of coffee, and I use the UP Coffee app to track my caffeine consumption. Not because I'm worried I drink to much, but just out of interest. I like the idea of Health as a center for all that kind of information, but at the moment there aren't any decent apps to easily track coffee consumption. (Or alcohol consumption for that matter) that integrate with Healthkit.
One month later and not an app that supports it has been released. It's either dead on arrival or Apple is going to push it more aggressively with iOS 8.1 and the iPad launch next month.
Either way: Siri, turn off the living room lights should be possible right now if WWDC is to be believed.