Its not just the app that's terrible, its also the moderation tools.
A large number of subreddits use the Reddit API as a moderation tool, because its better at searching / listing posts than the official apps. By increasing prices of the Reddit API, they've not only made 3rd party apps unusable, they're also about to make these 3rd party moderation tools unusable and unaffordable.
Reddit was Reddit because, despite all of the crap with the official app and tools, with enough grit and work, you can make your own tools, your own interfaces, your own CSS for your own Subreddit. All of that extra effort is being thrown away with these changes, and now we're all going to be stuck with the awful experience that is vanilla Reddit.