As for the software itself, the next beta release will have a vastly improved GUI, and will come in native PC, Linux, and Mac flavors. Part of the reason for the construct plugin delays is improvements to the file format to future proof it so you can continue to see new features far into the future. The next beta release for Spriter is the end of July. Improved GUI, improved performance, improved stability, cross-platform, and more....
Still a bit to do, but things are moving along very quickly. The next beta will be in your hands soon. Just bear with me a little longer.
As promised, here are some screens of the current build on each platform: