Autofill and Support - Necessary for the game or failure of a role?

People typically don't want to play support. There are exceptions but it feels like most people that are support tend to be autofilled. Most of my games, ranked or normal, tend to have at least one player asking to play another role. Is this a necessary mechanic or a failure to make all roles equal in power level and enjoyable? Thoughts?

Edit

We can talk about what role currently least favored all day but that isn't necessarily the point of the thread, although the idea is welcome to be discussed. Since there has to be an autofill feature, this would indicate that some roles are simply not preferential at some point in time for xyz reason. The topic is - is this something that is necessary in a MOBA or is it indicative of something flawed with the game, role/champion balancing, etc.