Agree.
Last minute change is certainly unacceptable. In my comment on June 10, 2015 in this thread, I proposed 12 or 24 hour time frame. In my opinion, 24 hour timeframe is far more reasonable, especially in a game with participants all over the world. Your opponent is quite possible still asleep and unaware of the change in 12 hours.
Match time change provides an option of home team manager to handle sudden matters. However, if a too short time frame is adopted, a change of match time may suddenly become another short notice sudden matter of the opposite team manager. In my opinion, if home manager's sudden maters are too close to match start time, the home team manager must accept this themselves. It is not good to transfer the problems to others and becoming their sudden matters.
Let us think. Without match time change, home team manager just cannot attend the match. He may still have some time to alter instructions to prepare for a match without attendance of manager. For the opposite team, their manager may not be able to make any change. His players may not be in full condition as they originally planned, or wasted some conditions which can be used to train and improve players. New match time may be close to other matches of away teams. Training plan of away may also be affected. Away team may also not be able to sell a player after the match as scheduled. In conclusion, it is possible that this gives lot of problems to the opposite manager. If the change is earlier or at least the away team manager is notified, the effect may reduce.
These ideas are also good.