According to a news from Apple Insider, Apple could possibly retain the Touch ID and the headphone jack on the next iPad. The report which comes from the supplier states that the screen size has not been determined yet. They also noted the next-gen of the iPad Mini will be released along with the next-gen iPad.
As Apple is happy with the current base model of the iPad, this round Apple is not planning to change the design drastically. This is because the previous gen iPad comes with Touch ID and added support for the Apple Pencil.