The grate is there to keep things from passing through that could clog or damage the impeller, and a tapered profile would just aid debris in getting wedged in between. Flat and straight is the best. Clutch is a huge asset in avoiding things from getting sucked up, and instrumental in allowing it to fall away in most cases. I've coasted over logs etc. to help wipe the grate clean. Very rarely have I had to actually beach the boat and pull the pump to clear things out.