I think there are so many fat ponies being shown nowadays, that it is just about impossible for judges. Of course in an ideal world, you would want a fit pony that was a great example of its breed, but if the best examples of the breed in front of the judge are also overweight, I am not sure what they are to do. I think lots of people would be of the opinion that weight is fixable (so long as the pony doesn't die or become ill due to a weight related condition in the mean time, which is increasingly more likely) whereas other faults e.g. back at the knee, are not.
My mares were out on the hill at lambing time and I didn't have much time to check them properly other than making sure they were upright, legs attached etc. etc. At the beginning of May, I was horrified by how fat they had become - with the warm winter we had way more grass on the hill than usual, and they are an absolute disgrace. They have been on a very strict regime since then and are improving, but are still huge. At the Highland Show on Thursday, my OH commented that he didn't know what I was stressing about as at least 50% of the ponies were bigger than ours. I think many people genuinely have no idea what a fit/fat pony looks or feels like, and certainly with repeated exposure to overweight examples of a breed, it is very easy to get an incorrect image in your head of what a particular type of pony should look like weight wise.
Having said that, there were also many beautiful fit ponies with good conformation and type, so it is not all doom and gloom.