Nope, or at least no one here has any plans to do it. Honestly, if anything happens to it, it'll be removing it entirely. It's a preview rendering feature that is rarely even useful for that. It came from a PBRT plugin that was designed just as an example of the technique.
Fully agree about removal. Instant (duh?) radiosity is a restricted bidirectional path tracing (BPT), which only brings correlation and singularity issues without any real advantage over BPT in a ray tracing setting, unless additional acceleration is used, like Lightcuts, Matrix row-column sampling, or any of the importance virtual point light distribution methods.