well, i'd honestly tone down the tyrant and one 'fex... having one T7, 5W 'uber death gribbly should be enough of a terror for your opponent to worry about! (plus the trygon!!!)
with the extra pts, you can get more gaunts, lots more gaunts!
gargoyles should never be ignored in any list in my opinion. having a unit capable of a potenial 24" move in one turn is just plain nasty! true they're not great in assaults, but they can very quickly stop enemy fire support units from shooting your bigger, meaner gribblies!
cheers!