This is absolutely preposterous. No other game forces their players to log out once a day, whether it be an MMO or other genre. This reminds me a lot like the old Fatigue system from back during 1.x, and it was seen as a colossal mistake at the time.
Look... I understand that the servers are being hammered with players clamoring to get in and play. But this won't solve the problem. If a server can hold a maximum of 10000 people online at one time, and there are 12000 people trying to log in, then there's going to be 2000 people left out in the rain looking in, even with this ingenious solution. Doing this forced logout will not fix the problem. Right now you're hoping that 2000 other players will get bored and logout during the day so that the 2000 left sitting out in the rain can come inside and get dry for a bit. That's been your "solution" for this problem for a years now, and it doesn't work. Players don't want to go outside and get wet, they'd rather force themselves to stay indoors. So your wise solution to this problem, is to kick everybody to the curb and force them to stand out in the rain for 10 minutes, before allowing 10k random people to get back in.
Do you realize that there's every possibility that the 2000 people left outside originally, are still going to be left outside after this? This is not a solution. It's only going to make things worse for different periods of time, especially when those 10 minutes are up and the 10000 people try to log in at once. Lobby servers will crash (again), and it will be another cluster of a mess. This will also make a portion of the players extremely angry that they were booted out when they had a boss at 5% (or less) hp because you are incapable of upgrading your servers to allow for more players. If you are literally, figuratively, and absolutely unable to come up with a better solution to the problem of "our servers aren't good enough to handle a large amount of people" than this... then I have to ask: What kind of game developers are you? You do not design a game with a maximum number of players in mind.. you're crippling yourself and disappointing players if you do that. Your solution of adding more instances to the popular zones is a step in the right direction, even though it partially annoys players because you do not allow them to choose what instance they get put into when they teleport in (which is another serious flaw in my opinion.) You have these instances around until enough players lose interest in the game that they drift away to do something else, and then you remove them.
If you are incapable of keeping up with player demand, then you realize have no business thinking of yourself as a competitor in the global market. No matter how good the game is, if you artificially restrict the number of people who are allowed to play the game because you're incapable of keeping up with demand, then you need to move to another line of work.