That's the point. Most fighters would have to move up a weight division, so mostly no advantage is gained. We still see the same guys fighting each other except at a higher weight = without half killing themselves cutting weight = better stamina = better fights.
There are not many fighters that would stay in their respective divisions. Edgar and Machida are the only ones that spring to mind.
Do you know what's crazy, I never sat back and thought of that. Great point. Only thing is I think if they did this they would need to make one more weight division in the form of a super hw of sorts. All the 205'er going up would end up running into monsters like JDS, overeem, brock etc. But Deep down I still think if the 205'ers didn't cut weight they would still do good, but against the top of the HW division, they would fail.
Tried repping you for that post but i need to spread it around.