I’ve done this in the past but used a body class for the feature. I find this works better as it’s easier to target a body class rather than an attribute, especially with multiple features:
Sticking with body classes is probably the path of least resistance. you could simply append any “features” you want to the body_class filter and be up and running with least resistance. A lot of commercial plugins make use of the body class filter too, e.g. gravityforms, others.