The only problem I have with Ronnie/Jason is, effectively, Ronnie
has to be the face of Firestorm because he literally offers nothing intellectually compared to Jason, who gets relegated to Professor Stein. I think the concept could work and really shine if Ronnie was given more character and wasn't treated like Joe Everyguy McCollege Student where he actually has his own area of expertise that can allow him to offer good advice/information as the voice in the matrix. But as of right now, he's (at best) just a cool guy along for the ride. Jason has to do all the heavy lifting and then you effectively have a white guy being piloted by a black guy who has to do all the work while the white dude gets to bask in the adoration from people they save. Every time. Not the best look. For this combo to work, you need each of them to contribute to where it feels like a real partnership. Making Ronnie an athlete really doesn't matter when Firestorm flies and mixes elements. Not sure how catching a Hail Mary for first down is going to come in handy in nuclear fission.
Maybe make him a film student who wants to be a special effects/pyrotechnics guy? He won't really be thinking about
how to make the elements work together so much as what they can do with them; he'd be creativity to Jason's intellect. That way they're always completing the other side of the matrix for one another.
Something that may work, which admittedly is kind of stealing from Shazam, is to make them adopted brothers and have them look out for each other and deal with how while Ronnie used to protect his nerdier younger brother, now he kind of
doesn't bring anything to the table and make their core narrative about how essentially Ronnie has peaked and needs to develop himself into someone better whereas Jason starts to come into his own. It works fine with them just being college friends too, but I really can't figure out how to keep these two together long-term where Ronnie doesn't just become the load or de facto pilot of Firestorm while Jason gets to be a talking head.
I think it works short-term but Firestorm with Ronnie was about Ronnie as quarterback and Stein as coach. There's not much else there. It can work, but he's the crutch as I see it. Which pains me because I like Ronnie a lot, but when he shares the matrix with Jason is when the dynamic needs to change.