I [wouldn't] say he [was] brilliant [but] he [is] competent at his job. ←← [would (not)]係 "will" 的過去式,表示委婉的語氣,而因時態一致性原則,be動詞用 "was" 過去式;“but” 連接詞的子句,be動詞用 "is",表示指在職中的勝任。
I wouldn't say he was brilliant==it is a sentence in subjunctive mood; while the other one ; but he is competent at his job==is to describe of what happened now. Yip