Whats wrong with bending at the waist to get more range?
Ok 1st problem your leaning in chin first and asking to be knocked out (well if you use the arm your not punching with to cover your chin your chin is now protected, also tuck the chin well, and also lean over to the side so its like a lean over and slip combined)
2nd problem, you loose alot of power by leaning in (not if its and overhand punch, and if you are throwing a cross you can use different power mechanics ie you can strongly drive off the rear leg or rotate the hips 1st before you lean over etc)
3rd problem you are vulnerable to uppercuts, if he throws an uppercut counter he is leaving himself open to a massive overhand punch, plus you have your elbow/arm covering your chin anyway)
So why cant I do this?