yeah different layouts work for different people and genres. i know a guy thts quite good drumming on a keyboard, but he cant get his head around pads and i'm the opposite. the give on keys throws me off.
figure out a layout that works for you first, and since hats, kick and snare are the basic buildingblocks theres nothing wrong with only being able to play those first.
once youve memorised your layout stick with it,.... kinda like a real drummer with a real kit, they dont mess about with it much.
one thing that you can do with the mpc is layer sounds so that you dont always have to hit the hat and the kick at the same time,.. juat the kick layered with the hat which frees up your fingers for a sec.
alot of great drum tracks have come from tiny set ups, nothing more than a kick snare and hat with maybe a ride thrown in.
oh and if you can, you'll want atleast 4 samples at different velocities, or even right handed hits and left handed hits. it'll add to the realism.