The cloud version of ST is open for many formats.
It will at least be possible to use current ST to upload to the cloud version, then the current plugin will work unmodified.
I have suggested that ST plugins should be usable with a minimal ST version with the sole purpose of uploading to the site. That app should be easy to get working on for instance Mac too (using Mono).
If a rewrite is needed and I and zingo get hit by a truck or something, the code is open sourced and in my opinon designed to be usable outside ST too. (I have dabbled some with GPSBabel, but there are some work to rewrite c# to C++, there are too many C# constructs used.)