Thomas really doesn't like Roman. Like, a ton? He reminds him of that gross old-style Gotham thing of gross street manipulation and cruelty that he escaped for a reason and Roman himself is, to him some irredeemable torturer douchebag who seems to live to antagonize him like a whole bunch of other Gothamites. He doesn't trust him, and while he doesn't think he's especially clever or that he'll necessarily be hugely successful, he's really wary of his control and potential power in the City.