I really think the governing bodies should just get real strict on the weights fighters can come in at. Basically you're getting much bigger men draining down to really low weights and fighting in the lower classes than they really should ever have any business fighting in! I'd prefer it if they had to weigh in on fight day no more than 3-5lbs over the limit and therefore stop bigger men fighting at much lower weights....they should really be fighting at what is their real weight class IMO. And fighters often say it kills them getting really low in weight anyway...so stop 'cheating' and fight in the class where you should really be!
They should bring back same day weigh-ins. If fighters are professional and fighting in their correct weight class, there shouldn't too much of an issue. Also, you shouldn't be able to fight for a title at a catch weight.
I've always supported the rehydration limit. IBF has a rule that prohibits fighters from rehydrating more than 10lbs on the same day weigh-in. I don't know if it applies to every fight they sanction but that rule should be improved according to all weight classes (except HW) and used universally. If they put it in place, we will see more physically matched fighters at fights and weight cutters will need to move up at least one division, some examples would be; Canelo, Brook, Porter, DSG (at 140), Rios, Benavidez, Nicholas Walters.
