When it comes to WCF XXI.1, I am in general agreement with the wording of the WCF, but I disagree with the intended meaning of the framers, and I disagree with the practice of those who follow the WCF. It would be difficult to disagree with a statement that says we must worship God as he prescribes, and not according to the inventions of men and Satan!
We must make some qualifications. Certain innovations should be permitted in church, but we should not necessarily call that worship. For example, I see nothing wrong with presenting a play, or puppets, or games when dealing with children, but that would not be worship. Church members can do all sorts of things together, including having coffee, playing soccer, etc., but that would not be worship — except in the very general sense of living in unity before the face of God. For this reason, I think that the main gathering should be reserved for preaching and such things, and not for plays and games.
You mentioned dances, and that would be a good example to make a distinction. I do not believe that performance dances should be permitted in a main gathering, and it should not be considered worship. However, the Bible indeed teaches dance as worship, when individuals are so full of joy that they jump and dance in praise of God, along with loud shouts and singing, as David and others did. This has been neglected and discouraged in traditional churches, to their shame. But dances and songs as performances to men, I would reject.
Then, as a cessationist document, the WCF in fact rejects biblical worship, and contradicts its own article in XXI.1. Paul said that when we come together, each one should have a song, a teaching, a revelation, a tongue or interpretation. And each one may prophesy one by one, so that all may learn and be encouraged. I do not say that this has to be done always in every Sunday or main gathering, but a church must find a setting for this to happen, otherwise, it would be in direct opposition to biblical worship. Also Jesus demonstrated that acts of kindness like healing the sick ought to be performed on the Sabbath. Therefore, the Sunday service should usually be accompanied by the laying on of hands to heal the sick, with miracles. Any church that does not do this is in disobedience.
The Bible mandates the participation of all members, and this participation is by the power of the Spirit. In this, the charismatics are far more obedient. However, they must learn to regulate these activities, as Paul also instructed.
Whether following the WCF or not, traditional churches often commit the same error as those who opposed Christ in the past. They are eager to follow the traditions of men, often in place of the commands of God, and forgetting judgment, mercy, and faith. As Jesus said, “Go and learn what this means: ‘I desire mercy, and not sacrifice.'” But traditional churches often force God to accept sacrifice, and do not teach or receive his mercy, such as in miracles of healing. And Jesus also said, “The Sabbath was made for man, not man for the Sabbath,” which many who claim to be rigidly faithful also forget.
I am not in full agreement with the wording of XXI.5, but I will not take time to explain in this reply. The above already goes a long way to make my position clear.