Moments like these would just poison a modern batman game since Bruce is nothing but serious but back then, with how dick was also a wise ass it just fit with him. Especially since he didn't talk in the arkham city challenge maps and you didn't see dick outside of the arkham origins multi-player. Arkham knight truly was the last gem of rocksteady before Sefton hill jumped ship.
There could've even been a sole nightwing game with dick in bludhaven or even him focusing on Gotham but nope... suicide squad is rocksteadys legacy and gotham knight for WB Montreal