Brendan Donohue, writing on the Twitter Blog:
Previously, Twitter for iPhone and iPad offered very different experiences. Now, Twitter apps on these devices will be more consistent regardless of which one you’re using. Starting today, iPad users will be able to create and see revamped quote Tweets, explore trending topics in search, visit product and place pages, and more. We’d like to tell you how we made this happen.
Although they shared some code, Twitter for iPad and Twitter for iPhone were originally developed and designed separately. Each app was tailored to its platform — but required a lot of extra effort to develop. All too often, this meant that Twitter for iPad features lagged behind other updates. To fix this, we had to rethink our approach.
The good news is that Twitter's iPad app is now mostly at feature parity with the Twitter iPhone app. The bad news is that Twitter's iPad app doesn't exactly use the extra screen space of the iPad efficiently, and instead is mostly just a scaled-up version of their iPhone app.
Modern iPad design pic.twitter.com/akzIREgePI
— Federico Viticci (@viticci) September 9, 2015
This is probably explained by the fact that Twitter has been working hard on rebuilding a solid foundation across all their platforms to ensure feature-parity, as they explain in their blog post. It may just be that they wanted wanted to get something out the door and (finally) update the iPad app and they didn't get a chance to fully adapt the design for the iPad. That might be naive of me, but I'm sure there are some at Twitter who recognise that this update still leaves a lot to be desired when it comes to a good iPad Twitter app and will work hard to continually improve it.
What we’ve got so far is a baseline to make everything work well. It’s been a huge effort to rewrite the system in place as seamlessly as possible. One of our first steps was building landscape support, which we shipped for the iPhone 6 Plus earlier this summer. From this effort, we learned a lot about how and when to adapt to changing conditions. This was the foundation on which we built our updated iPad support. Now, we have new tools that are more robust and allow faster iteration. Adaptive UI gives us the ability to support new devices and bring new Twitter features to people faster. But as you might expect, from time to time there are going to be some differences in features and functionality between devices. In the future, we aim to get Twitter for iPad and iPhone to complete feature parity.