It's really not all that hard to catch falls. On something like my 4th or 5th climb ever I caught a 15' leader fall from a leader falling out of my direct line of site. (High Exposure crux.)
It takes a lot more experience to become a great belayer with anticipation and all that, but lets not pretend that catching a fall is rocket science. Very few people get dropped, and when it does happen it often seems to happen with experienced people (complacency?) and a lack of communication involved.
Having said that, most people are smart enough to lead well within their comfort level when with a new climber.