My own view is that the 5e went way to far in eliminating long-term mind control. One of my all time favorite modules is Against the Cult of the Reptile God, which completely fails to work if the villain's charm only lasts an hour. There needs to be some kind of mind control/mind influence that lasts for weeks or months, at least on commoners. It's fine, however, if there's a quick counter for PCs, as long as the counter is not something that can be readily scaled up to quickly free all the slaves.