Generally, I agree, but there are a few toons that do good slow.
Baze, for example. My arrow, triangle, circle, and cross are all health mods with protection primary. He doesn’t need speed, as he gains TM with enemy buffs and if he is slow he taunts longer. That way he has over 83k protection.
Ventress can work with offense primary and a set of crit chance to increase her stacking damage from her unique and ensure she crits. She gets speed from enemies with no buffs and TM gain from deaths. you can boost her other stats instead of speed. Same for reworked Vader.