The Lord directs the brethren for the church according to the righteousness of the members
Christ himself said, when he appeared at the Kirtland temple:
D&C 110:8 Yea, I will appear unto my servants, and speak unto them with mine own voice, if my people will keep my commandments, and do not pollute this holy house.
Obviously the Lord doesn't stop his servants from receiving any personal revelation except based on their own worthiness and preparation.
But with regards to revelation for his church, the principle is laid out in this verse. The Lord will appear to his servants and speak to them if the people keep his commandments and do not pollute this holy house. That "if" is important. If we want more direction from the Lord as a people, all we need to do is keep sacred things sacred and keep the commandments he has already given. If we do not do that, the brethren, be they ever so worthy, will receive their needed personal revelation, but the Lord will withhold his answers to the church. Let it be clear in our minds that such circumstances are embarrassments for the body of the saints, and not embarrassments for the prophet and the twelve. They are worthy. They are the Lord's chosen vessels.
At times the Lord has been slow to give guidance until the people have been worthy, or have been willing to repent. One obvious case was the revelation that came to Lorenzo Snow that the saints needed to pay their tithing if they wanted the drought to end. The Lord did not appear in this instance. But it was still an answer by revelation. The Lord could have told the Saints immediately, before they suffered a drought at all. But when we are disobeying a commandment the Lord already gave, it may take significant time and penitence before the Lord makes the cause of our discomfort known to us.