Ha! I was thinking the opposite.
Ronnie is a little much like Stein, being the super-genius particle physicist who's also less of a 'player' and more of a straight-laced long-term 'family' sort of guy (who would be as likely to spend time thinking about his long-distance disrupted relationship with Caitlin as Stein did his own family issues).
Other than neither of them being fifty, Jax and Ronnie are about as different as two dudes can be.
On the other hand, the Waverider, particularly now that Amaya is gone, is a little dude-heavy, so unless Gideon gets a 'robot body' that looks conveniently like the actress that portrayed her last season, the ship could use another woman, and having the next Firestorm Matrix Compatible person be a woman could make for some funny awkwardness (particularly if her and Jax don't inevitably fall in love as a result of their forced intimacy, but instead adopt a more siblings-who-pick-on-each-other dynamic).
On the other, other hand, the ship's got a lot of people on it already, and Jax being able to Firestorm up all by himself would certainly save cash on hiring another actor to be his 'other half.' And, con for the writers, it would give them one less excuse to desperately come up with for why Firestorm can't be seen this episode (since they fight like hell to separate Stein and Jax, so that they don't have to spend money on those effects, or worry about a flying man throwing fireballs steamrollering their weak adversaries that are rarely a challenge for Rory and Sara, let alone people with powers)...
lol I just said the same thing where both Ronnie and Jax are involved. the only they have in common is they are both younger then stein in this universe. But ronnie is a full flegde scientist as I said snd not a jock.(like he wasinthe books and animated series )
he's just a good looking really fit Nerd. from that the live action show pushed. So while I'm ok with drcomic's suggestion to a degree I'm good with ether. the show does need another female
it's possible amaya might come back though. we'll have to see.
But I meantioned my sugesstion above. Anyway in the live action universe they don't have that much in common other then thay are both younger then stien. And jackSON was just an ordinary jock turned car mechanic before joining the crew of the wave rider. and learned to fix that shipway later. he's not lowest intelect ever seen,
but he's not some one with a PHD un like Stein and Ronnie in the live action universe.
And Ronnie in the book's although he became a teacher. he was a coach and not a scientist. he was smart , But I don't think he ever became psychics major ,unlike in the live action self in universe of the flarrow verse.
No jax and Ronnie aren't that similar and that was made clear with the way caitlin treated hjax when looking for a new partner for stein. it was in a way that was unfair and came off looking like another issue.
But it was due to missing Ronnie and what made him "Him" in which she fell in love with ronnie. Sadly it was shown poorly. but ronnie being scientist was a factor.
But it was clear it was about live action Ronnie being a scientist. And before some one goes to discredit that, let's also remember barry wasn't much of CSI due to the writers messing around in seasion 1 til he met kara on earth 39 and showed he had brains on her earth be side talking and being talked about . And they had Cisco and Caitlin do all of the foresnic work like Felicity asking Caitlin to do DNA test's for sara's KILLER etc. And barry was right there for her to ask from the jump/the whole time.
which was freaking strange for barry and his day job. keep in mind the writer's have made a lot of weird mistakes in all three series.
Anyone not recognizing Ronnie as scitenist is their ( the writing team of flash's)fault and so was alot of other glaring mistakes where Barry was involved and alot more screw up's in arrow as well where detective work & details with foresnic's were in involved like having felicity do that and putting suspicon arsenal and stupid pointles chase of criminal that weren't there when sara died and Dna didn't match who tocuhed the arrow like komodo being sara's killer. that was the stupidiest plot ever.
It was just bad writing, All around that same time period. sadly to say. And they are owned by a company called detective comic's entertaiment.
But the CWtv writers that have taken these characters barely live up to that, where their characters come from. always keep that inthefor front of your minds.