Thanks for looking into Adobe Fireworks for UI design tool.
Fireworks continute to be the best UI screen layout design tool and will (can) not be replaced with Photoshop.
We cannot disclose any future version application, but all I can tell you that we are working on quality improvement and looking into the best practice for the web design worklfow.
Fireworks Product Manager
Hope that means a better memory handling and stability in future versions.
If Fireworks is going to become an industry standard it should get rid of those irritating bugs once for all instead of dragging them from version to version.
The place to give official input/feature/bug requests is not here. This is a user to user forum and rarely monitored by Adobe staff.
Use the feature request form at https://www.adobe.com/cfusion/mmform/index.cfm?name=wishform