The scoring rubrics released by ACT are just a suggestion of how essays might be graded.
My own students are writing much worse essays for this new format than they did for the old SAT or ACT essay format. I would certainly give them lower grades, but it is impossible to tell how much lower.
It would be really helpful to have a collection of actual essays people wrote during the test and the scores they received. Anyone who is willing to post his or her essay and score – thanks! (assuming this is allowed by the moderators…)