A tool like this really should allow for links to be drawn in the Screenflow tool. Manually adding links via screens is an exhaustive means of achieving it (a means to an end, but certainly not a great solution), this tool should be aiming to make the whole process faster and less exhaustive. I expect a wireframing tool to cater for such needs.
Even if it's just adding extra lines/arrows/shapes/text on top of the links created via the exhaustive method, that'd be extremely useful.
Any chance of implementing such a feature?