might consider some of those bunk slicks, would help in the loading process but might make it worse on the launching since I've read those things are slicker than snot. You should be able to drive further up on the trailer with less power, and then winch it the rest of the way.
I use a steep ramp at times, but don't have the slicks on my bunks, I can back my trailer in deep enough to where I can just drive on within 6" of the front roller/winch under low power (a bit above idle). That is something else to consider is how deep are you backing the trailer in when loading up. Try dunking/wetting the entire bunks/carpet which may help as well or adjusting the depth of your trailer (back in further) when loading. If the trailer is not "made " for the boat, its a trial and error thing until you can figure out what works at certain ramps.
GO BIG ORANGE !
I meant to behave, but there were just way too many other options available at the time.