You misunderstand me, sir. I personally would like to see more Support style classes, my concern is that in 4 man content where a support class contributes the least, it makes completing the dungeon harder for the group overall and also adds more non tank/healer jobs which will make it harder to group up due to a higher disparity between tank and non tank types.

I say that support contributes the least in 4 man because generally support classes support in specific ways that are of benefit to one or 2 types of people. There is a big difference between making up to 3 people stronger and making 5-7 people stronger. This is assuming that all members are receiving a bonus from this class. It's more likely that a support type will only be able to help one type of class do better at a time(Bards can only perform one song at a time for example, so they are only benefiting 1 type of character at a time.)

This is why Bards are usually not using their songs.