The following features are planned for upcoming versions of the ProcessWire core. These are not the only features planned, they are just a taste.
ProcessWire 3.1 / 2019
Add support for predefined crops in our image tools. While this capability is already available with 3rd party modules, it's been one of the more common requests in the core, and we think it makes sense.
Add support for custom properties in file/image fields. Currently just description and tags are supported, but it's clear there is strong interest in supporting more here, so we look forward to adding this.
As always: continued performance and security optimization to the core, and continued improvements and optimizations to core API variables and functions.
This roadmap is not comprehensive and is subject to change depending on team availability and priority adjustments consistent with the projects ProcessWire is used for.
New versions are released just about every week. To keep up-to-date with the latest additions, use the ProcessWire dev branch.