No, the studios probably don't think it's a good idea.

Vin Diesel really loves Riddick. It's his passion project. Universal was willing to let the franchise die after two films but he wasn't, so he did a cameo in Tokyo Drift in exchange for the rights to the franchise. Then he independently raised funds for the third film and fronted a bunch of his own money, going so far as to mortgage his house to keep the production afloat.

I'm sure it's the same with this fourth film. The series was never all that profitable so the studios wouldn't push to make another one. It's gotta be Vin Diesel pushing to have it made because he personally deeply cares about the franchise.

I was just saying to someone that I think Riddick is one of those characters who are better the less you know about them, like the original film.

Of course all the sequels try to answer those questions.

On the other hand, the Xbox game, Escape From Butcher Bay, was one the better film tie-ins I've played.

You mean like xXx?