Don't Wait If You Can't Wait Much Longer
Don't wait for the 2019 iPhones if you need to upgrade your phone in the near future.
The new cameras, Apple Pencil support, and an improved design might sound great, but don't expect a surprise launch in June, July, or August.
Apple only has three iPhone launch windows. The first takes place during the spring in March. The company's March 25th event came and went without an iPhone launch.
The second window takes place in June at the company's annual WWDC, but Apple typically doesn't announce new iPhones during the keynote. Apple announced new hardware (Mac Pro) during WWDC 2019, but it wasn't related to the iPhone.
The final window is the fall window in September/October. This is when you can expect Apple to reveal the 2019 models for the first time.
Again, a leaked Verizon marketing calendar points to the 2019 iPhone event taking place sometime in September with a release shortly thereafter.
Apple's new iPhones are likely three or so months away from hitting shelves. If you don't think you can sit through a year of rumors and reports or don't think your phone can make it until September, you need to start looking elsewhere.