No rematches for dethroned champions, even if they are an undefeated GOAT with 12 title defenses who got KO'd in the final five seconds of a fight they were dominating. They go back into the queue with the rest of the contenders and work their way back up. Only exception is if there is some legitimate controversy like blatant fouls affecting the course of the fight, a contentious Split Decision, etc.
There's no such thing as weight bullies or reach bullies. If you can make the weight and fight effectively then you're not too big for the weight class. Every fighter has a different set of attributes to bring to the fight. Some guys are really good at cutting weight or blessed with Go Go Gadget reach just like some guys are naturally faster or stronger or punch harder or have a better chin or have prime BJ level superhuman flexibility. It's up to the fighter to develop a style that best maximizes his strengths while minimizing his weaknesses.
Been saying this for years. Half the time the label gets tossed at any fighter who happens to be tall relative to their peers in a weight class (regardless of their actual build), have a style oriented toward heavy top pressure, or just based on where they're from. Even if they
do cut large amounts of weight, so what? If they're making the limit they're making the limit.
Like you said, every fighter has their own personal physical strengths and weaknesses. I'd be on-board with calling people weight bullies as soon as people start calling Jon Jones a "reach bully", Max Holloway a "chin & cardio bully", Lewis a "power bully", or Volkanovski a "low center of gravity bully" lmao. It's absurd. And what's even funnier is that a lot of these traits: durability, reach, power, cardio, etc. are inherent/genetic to a degree and they also don't bring significant drawbacks (unless you rely too much on your chin long-term of course). Meanwhile, cutting large amounts of weight requires a good team and a level of commitment to dial it in, exposes you to a lot of health risks in the short and long term, potentially wrecks your cardio, and makes you more susceptible to concussive damage inside the cage.
I don't
like weight-cutting as an institution and I wish the sport could do away with it or move towards a system where fighters are compelled to fight closer to their natural weight somehow, whether that be through hydration tests, same-day weigh-ins, CSAC-style weight comparisons, or some combination thereof... but as it stands with the current system in place I think it's funny that we all pretty much acknowledge that fighters have to cut some amount of weight to be competitive yet we have this arbitrary limit in our brain where XYZ amount is
too much and the fighter is now "cheating" even though they make weight every time.