I agree with Rsknight11. Too much signage can really ruin the atmosphere of a mountain. Three or four designations (depending on the range of terrain) should be sufficient. However, there are those runs that appear mellow at the entrance and then you hit the "edge" and OH WOW! Not so easy! I do think an additional warning at those entrances to the runs is probably wise if the mountain only uses green, blue, and black designations.
How would 5 trail ratings be more signage? It wouldn't
Your suggestion of additional signage, would be more signage...
That makes zero sense