This page describes the planned development of Synergy. There are no dates or deadlines. Instead, you'll find the features to come and the rough order they can be expected to arrive.
Synergy should work seamlessly. When it works correctly, it works transparently so you don't even think about it. When it breaks, you're forced out of the illusion of a unified desktop. The first priority is fixing those bugs that break the illusion.
Some of these bugs are pretty minor and some people would rather have new features first. But I'd rather fix the current foundation before building on it. That's not to say features won't get added until after bug fixes; sometimes it's just too tempting to code up a feature.
Some features fit well into Synergy's current design and may simply enhance it's current capabilities.
Two features stand out as long term goals:
The first feature means sharing a monitor or monitors the way the keyboard and mouse are shared. With this, Synergy would be a full KVM solution. Not only would it support a few computers sharing one screen (still using the mouse to roll from one screen to another), but it should also support dozens of computers to provide a solution for server farm administrators. In this capacity, it may need to support text (as opposed to bitmap graphics) screens.
The second feature would enhance the unified desktop illusion. It would make it possible to drag a file and possibly other objects to another screen. The object would be copied (or moved). I expect this to be a very tricky feature.