There used to be a similar argument in ff11 about needing less people to do events.

Something like a party of 6 should be able to do anything, simply make things weaker so a party of 6 can kill it but still be hard. The problem is, if 6 people can kill something, its not hard, even if its hard for you, it took almost no cooperation with others and most likely very little strategy. Something that would take 18 people and still be hard is many many times more difficult.
You only having 5 friends shouldnt be my problem either.