Hi Nuno,
Thank you so much for your idea! I’m marking this as Implemented because since version 2.6.13 we have an useful class "is-horizontal" that you can add to the RadioGroup to show the options horizontally. It isn't an input parameter but allows you to achieve that use case.
You can check all the useful classes in our CheatSheet.
Cheers,
Jéssica Mendes