I agree. I fact, I think the services of the actress cast to play the role of Poison Ivy (and indeed of all fictional characters conventionally depicted with red hair) should be openly procured in accordance with a selection questionnaire weighted as follows:
Part 1
(Mandatory requirement)
(1) Actress's hair is red. (pass/fail)
Part 2
(80% of overall weighting)
(2) Extent to which redness of actress's hair reflects natural pigmentation. (40%)
(3) Vibrancy and degree of redness of actress's hair. (25%)
(4) Similarity of customary styling of actress's hair to hair stylings found in images randomly sampled from a Google image search for "poison ivy hair". (15%)
Part 3
(20% of overall weighting)
(5) Actress has tweeted a statement either expressly or impliedly favourable to Warner Brothers, DC Comics, or related products, characters, and other associated intellectual property. (15%)
(6) Actress is adjudged competent. (5%)