This is all well and good but the clubs aren't just complaining about these slots (MNF is gone btw, not sure why it's relevant to the discussion now). Across the 16 clubs, pretty much every timeslot is receiving complaints. Sundays don't suit Club A, Fridays are ideal for Club B, Saturday nights are the only time Club C can draw a crowd and so on.
And for what it's worth the Friday 6pm slot actually isn't going as badly as most predicted. For crowds at least I wouldn't be surprised if it outdraws MNF from years past.