If this is actually based on decompilation, they're going to get sued into oblivion. If it's a reverse engineering project based on behavioral observation... it's probably relatively thin, and the question becomes whether the maintainer(s) are going to invest enough effort into it to merit user trust. Given how massive the feature sprawl of Adobe CC is, getting from zero to something is pretty easy. Maintenance, completeness, and meriting trust are a lot harder.