Personally, I've advocate re-adjusting the weights slightly to reduce the problem. If someone is naturally a few pounds above a weight-class after fight camp he shouldn't be forced to jump 15-20 lbs where he is undersized and he knows it, because the opponents he's facing are going to be not 15-20 lb larger but significantly larger (25-35 lb).
130 FLW
140 BW
150 FW
160 LW
170 WW
180 MW
190 Super MW
205 LHW
265 HW
I think this re-adjustment alone could fix most of the issues with weight. You don't need the 2 or 3 new classes as some advocate, just 1 new class. It helps fighters who fall in-between MW and LHW. And everything below WW, move up by 5 lbs. Eliminates the massive 15 lb jump from LW to WW, and increases the competition pool for Flyweight which is seriously needed.