I honestly don't have a lot I want to change. And I'm not a fan of change for the sake of change to be new/shiney.
For the menu, keep in mind it targets 2.3. OEMs are supposed to display a menu button when an app registers a menu command. That they don't is annoying. For the record, AOSP from Google does. So any Android that doesn't, the manufacturer went out of their way to prevent it. The only way to avoid it is to rewrite the UI. I have considered adding a menu button to the existing button bar. It's not perfect, but might work. The down side is there isn't a lot of space on it. The "standard" place would be on the top left, the app icon is there now, and when tapped it goes to the main reading screen. I don't have any data about how often it is used. I suspect a number of people don't even know it's there. :) I didn't do it for the last release as I suspect it would be annoying for users without a bigger UI change to tip them off that it's different.
As for the web content... That's tricky. There are a lot of dependencies on the server side, which I don't control. I suspect there is throttling at play, the remote site doesn't like us hitting them with many requests in a short time. Web caching is tricky and getting worse. Many sites use live scripting to display their content, and since we aren't running a browser to download the content, we aren't running the scripts. A number of sites really don't like the way we do things. They want all that crap to shove their ads at you. So they try to prevent it. It might also look like "scraping" to them. I guess it sort of is in a way, but for your own personal use. It's not like you send the content anywhere. But they can't know that. I've tried slowing it down a little, it helps with the failed downloads, but it also means wakelocks stay up longer. That means more battery use. Perhaps I'll try to make it user configurable. Maybe even per feed. But then per-feed settings get cluttered.... I really wish Google had made the "reading mode" from Chrome API accessible. It would be cool to feed it URLS, have it download and send the content back for storage. One thing I've considered is trying to get AMP pages to work cached. They would be lightweight, already mobile friendly. Not everyone supports it, but it might be interesting.
I am always willing to consider ideas and code submissions. If you know a developer that wants to donate some time, have them contact me and I'll help them get started, merge pull requests, and post updates to the play store. I had a request to support innoreader recently, that might happen as the API looks to be compatible with The Old Reader. I am considering UI ideas. The simplest option is to use Material. It would look a lot like GMail, but I guess that's what people are into these days. I personally think it goes from one style of "somewhat boring UI" to another in that case... That's not really a bad thing, it's not like there are a lot of opportunities to dress up a list of articles. But if you have some ideas, try drawing them up in a wireframe, photoshop, whatever you like to use. Or even write an "app" that's just a UI to display what it looks like.
The first thing to do to really make a new development push is to get it building in Android Studio. Right now, it uses the old Eclipse based build system. I had started that, but had to drop everything because Google decided to be annoying about permissions.