Newer engine and clutches isn't a surprise on a Kohler engine, they've had teething issues.
They do engage at higher rpms than most other machines, because that's where the engine starts making power, which is also why they are hard on clutches and belts... But once it's going it should pull nicely and smoothly.
Make sure your getting full rpms, 3750-3850 if not adjust all the Freeplay out of the cable, you can also modify the pedal slightly to get a little more, don't go crazy, 4100 is the limit if you lots of flat out running. Tweaking the fuel screw on 1-1/2 turns helps too, just don't tell the emissions people lol.