Between Freeza and Cell, Dragon Ball has always shown these two to be different flavors of evil. Freeza is an evil tyrant and Cell is an egocentric battle-maniac. Despite being similar to each other, the two villains don't have the same goals or motivations half the time. That's not to say people wouldn't be excited if both of these villains made a comeback or were reintroduced. However, Freeza is the only one of the two to be given that luxury, even being considered for the Tournament Of Power as a last resort. However, that took convincing from Goku and a promise of resurrection back to the world of Dragon Ball.