Although I am in general agreement that the responsibility of an elder is to preach the Word. I am sure you would agree that a good Catechism can be a valuable tool would you not? If that is the case, would your problem be teaching a Catechism in a formal worship service such as Sunday night?
I am reminded of what CH Spurgeon said concerning a good Catechism.
Hmmmmmm, my comment was in regard to the OP, i.e., the preaching of the Word, ascertaining its meaning and making a proper application of it.
1. I am not averse at all in using a catechism for teaching purposes in the home and in the churches educational program. Men called to the ministry are to preach the WORD of God not some man-made document regardless how faithful it might be to the Bible's teaching.
2. So, yes I am 100% opposed to the preaching of a catechism, e.g., the Dutch churches' tradition is to preach through the Heidelberg Catechism in the evening service. As I have already mentioned, what should be done is to preach on one of the proof texts that is used for a particular section of the catechism or confession.... "faith come by hearing and that by the Word of God". Not everything in any confession is infallibly true, e.g., Chapter I, Article 17 of the Canons of Dordt has no biblical support whatsoever and interestingly enough not one passage of Scripture is offered to substantiate that article.
3. Preaching the WORD also provides a most valuable asset to those who are present; assuming
of course that the one preaching is faithful to the Word in its interpretation and application, for it also serves as an example for the proper way to read and understand that Word. Preaching a catechism offers no such asset, which I believe is one of God's intentions of having the WORD preached; i.e., that the people of God may learn how to 'rightly divide the Word of truth'.