I really do not like the way it appears to be done.
1- 30 days is too short a time. I'd consider it if it were half a year
2- Instead of the game deciding which players are eligible, the Guild Leader should have an option to choose the order in which the Leadership should be awarded. Some people just are not the right kind of people to be leaders and that can just destroy a guild.
3- Before awarding Leadership to someone else, the original Guild Leader should have a word on the change even if he's not in the game.
4- Players can always just create a new guild. If the problem is the guild bank, my first reply is that they shouldnt have placed the items in the bank in the first place. my second answer is that a GM could just decide how to deal with the items in the bank, example, split the gold between the 2 guilds.

This will cause problems with players knowing that the Guild Leader has to stop playing for a couple of months and requests a Guild Leader change followed with stealing everything from the guild and leaving.