hello i am a lvl 18 swashbuckler and my subodai just promoted, i tried him out and i dont know if hes too good. sarah steele and fan flanders just seem like better options, is there some way i can make him good?

Short answer: Yes.

Long answer: It depends on where you are in the story. If you're in Valencia or Cool Ranch, maybe not so much unless you're willing to try different strategies out until you find one that works. I'd run Fan, Bonnie Anne, and a third of your choice during Cool Ranch, either another swashbuckler, your Presidio companion (unless it's Dead Mike), or a tank that can take some of those heavy hits. Subodai will be of immense help in MooShu as the difficulty there is quite a bit higher than Cool Ranch; keep him leveled and make sure you're familiar with how he plays. If you're planning to try him out, I'd make sure to absolutely give him at least one rank of bladestorm and relentless if possible, and build those up as he gets to higher levels and promotes. As for talents, make sure he has some accuracy, armor/resist, and damage on him as he'll need those boosts to be more effective down the line.

he already has vengeance strike, should I get him vengeance strike 2? i also gave him blade storm already