I agree, this is a time period where people are busy with work or school and creating a character on x5 (which is far lower than x20) can actually be pretty bad since people would get bored soon. I leveled up my DK on Icecrown from 55-80 in about 24 hours of gameplay, which is aprox a week of doing quests 3-4 hours a day, which is still a lot to spend on wow during the weekdays. Lets keep in mind that is DK so the leveling is a bit faster than usually. Leveling up on x5 rate would increase that time by 4 and it would take a month minimum of questing, or even more since many players are not familiar with quests and their objectives.