Speaking in Bayesian probability, it's bad if life forms found on Mars are more advanced than human, and good if it's much less advanced, or even very primitive (as it means the Great Filter might be at an earlier stage than us right now).
And it won't be the former case, for obvious reason.
Finding life on Mars would still change one of the polynomials of the Drake Equation, which would shift upward the overall expected probability for intelligent life in the cosmos, which is probably what leonardzen means.
But "we don't have enough data yet" still seems like a good answer to the Fermi Paradox anyway.
It would shift upward the overall expected probability for intelligent life at our level. However, since we have no evidence of life beyond our level of intelligence, it also increases the probability that civilizations will not survive long enough to become much more advanced than our civilization.
And it won't be the former case, for obvious reason.