Before the changes #1 was easy with 4 people (3x SMN +BRD). Now it should be a joke.
Now it seems almost all fluxes can be won with ~12 people (non pet/ranged). We usually do 1 tank/DD party & 1 party of BLM/SCH/Magic dammage (or SMN if they do not have a nuke job) . The biggest problem I've had is random people who come in and have no concept of what to do/following directions (if there is 12-18 people from same LS saying what to do and 2 random people who should you listen to?). An example is #15 we clear everything since it weakens the boss and about 50% of the time some random person comes in and runs to boss even though we are fighting at top of stairs near entrance and then runs back and brings everything on top of us.
WoE seems incredibly easy now if you go in without a balanced setup and non brain dead people.