All we need is the basic signs. Stop, road crossing,, that sort of thing. I have helped put up signs and it's a bunch of people thinking where to put the sign for the corner,,how close to the corner,,, how far away from the corner,,,etc,, does this represent a corner,, it's people like you and me thinking where, if, how far,,,,.I ride with me own eyes and trust them only, anything else you are asking for a problem and the responsibility comes off the rider.
Signs can be a help but like everything else we have become dependent upon them and believe we need them. Anything crossing the trail is good to know. Just because sleds can go real fast doesn't mean they always should.
Personally I believe the rider will have to step up now and ride accordingly. Sure there me be more or less deaths but will that be the fault of the sign or lack of sign?