Though I suspect that, by the end of this season, Steven's going to be faced with someone who isn't interested in being reasonable.
He already has, if you consider Jasper/the season 1 finale. While it made him more cautious about his non-Gem loved ones, it hasn't shaken his core (yet).
And at the same time, Finn's still willing to talk stuff out if it's apparent that there really isn't any reason to kill anybody. I mean... for fuck's sake, he hangs out with Marcelline (an actual evil vampire who does mean stuff) and Princess Bubblegum (an honest to god dictator) and is still able to find redeemable features in both, even when they lie to him or use him... and it's REALLY hard for young men of that age to move past rejection and still want to be friends with the people who rejected them, but Finn is mostly fine with PB and even Fire Princess at this point.
Finn does talk things through, but his first instinct in a situation is usually to attack. He isn't without reason or sympathy, but his tactic is usually "conquer, then resolve". Steven, on the other hand, only fights if he has no other option, and even then, his powers are usually used to keep harm away from himself or from others. For Finn, it's important to him to have a sword and over-power his opponents as quickly as possible. For Steven, he's happy to give away his sword, and try to keep others from physical harm, by shield, bubble or negotiation. They both do try to look for the good in others, but their paths that get them to that point are very different.
I will give Finn a lot of credit for learning how to handle his relationships like an adult, in the cases of PB ("just because you have feelings for someone doesn't require them to feel the same way back, nor should they be punished for it") or Flame Princess ("don't play games with someone's feelings"). He makes mistakes, but he does try to atone for them.