It depends on the reason for the weight class changes. Like Couture going up or down in weight for the challenge, I respect. At the same time, there is something to be said for continuing to run a division. It's not like there isn't plenty of tape on GSP or A.Silva, but people cannot beat their styles. They have fought faster men, bigger men, more technical fighters, brawlers, wrestlers, etc. They have so far proven that when it comes to putting it all together at that one weight class, they stand alone.
A little boozed up, but in summary, I respect them evenly as long as the challenge is there.