I'm always on the fence regarding Starter Boxed Sets: first of all, because I'm usually only interested in Starter Sets from the games I already play. So, everything regarding lighter rules-version, pregen characters, summarized explaining of the world, etc are of no real use to me. It's just the little extras (custom dice, maps, tokens,...) that catch my eye.
That said, I think a Symbaroum Starter Box could be of interest for Fria Ligan once their 5e adaptation is fully developed. The Starter Box could then contain both rules set, those for 5e that just want to give a try to this new setting, and the original Symbaroum ones. This way, 5e players and GMs could take a look at the Symbaroum rules, see that they are not hard or so different from what they know, and could give it a try. I think, in that regard, the Starter Set's commercial objective should be more aimed at porting players and GMs from D&D to Symbaroum, than to introduce new people to Symbaroum directly.