I do not think the difficulty will change for a few reasons.
Firstly, recall that students pre-2015 have a table of standard integrals. However, this did not stop the board from asking stock standard "Evaluate X integral" straight from the formula sheet. In actual fact, in 2010 HSC Q1 (a), they explicitly said "Use the table of standard integrals to find X". If the theory that has been going around (there will be no more calculation questions because they're too easy now), then the aforementioned type of questions would not exist.
Secondly, observe that no context was provided for the formulas. In other words, the variables were not defined. Without the definition of the variables being provided, the formulas are of little use to somebody who has not learned/forgotten the theory. How can a person use the trapezoidal rule if they don't even know what 'h' is? Sure you allow a few rote learners to gain some free marks perhaps, but the benefits outweigh this.
Thirdly, these formula sheets were designed specifically to target students who misquote or are unable to recall the formula explicitly, but understand what the variables are and how they are to be used. So when students lose marks, it is because they deserve to lose them (ie: not knowing how to use the variables, not knowing what they are etc) as opposed to losing them simply because they misquoted formulas. This is the purpose of an exam after all.
