50 lbs of draw weight is plenty for most any North American (and a few African) game animals -- including elk. It depends on shot placement, broadhead sharpness/design and the arrow itself.
But if the arrow is crap, the shot will be crap -- no matter how expensive or "fast" the bow is. All the bow does is send the arrow on its way....
Think about it: Native Americans (to name only one "primitive" culture) were taking elk, bison, deer, bear, etc with bows of less than 50 lb draw weights before the Europeans "discovered" the "New World". They obvioulsy were using equipment of high quality and high efficiency, including their arrows -- and with deadly accuracy.
Without good arrows, made for the bow/archer/use combination, whatever bow you choose is just another bow.
Addendum: Don't use field/target points on small game. Use blunts -- they do more actual damage to the animal than field/target points.
Addendum 2: "Judo" points are blunts, they just have a fancy name. :-)