My understanding is that the weak knees were specific to the Black Rodimus version, and not a big issue with the original.
It can't be ruled out altogether, but I'm sceptical Rodimus Prime will get an all-new mould. The existing one is already very screen-accurate, at least from the front. The problems with the original release were addressed in the 'version 2' production run, so by now it should be a solid figure.