I recently got my certification through NPTI and got a job at a gym that will remain nameless. There is only one trainer there that is very big, the rest are typical trainer types. But I don't think the point is that they look like shit, it's just that their goals are very different. Most of them have fine bodies but they aren't interested in putting on size or gaining strength. They mostly seemed concerned with having low body fat with a little muscle, which most of them do.
Now as far as the advice thing goes, you and I both know that 99% of gym goers don't know what the hell they're doing. I'm not saying that personal trainers in general DO, but they at least mean well (at least the ones I work with) and they do possess SOME knowledge.
The thing is, a typical client is a horribly out of shape 40 something year old with bad diet and no gym experience or very little. So, yes I believe every trainer I work with can help these people. Now, would I send an athlete of any type to one of our trainers? Probably not. But for the general public I think they can definitely help as most client's goals are simply weight loss.
As far as progress goes. I myself am bulking at the moment, much to the dismay of my boss. He said I was getting a little chunky the other day (the scale said I was officially 200lbs so I was pretty stoked) and I told him I was trying to gain weight. He was quite perplexed as he didn't understand why anyone would want to gain weight during the summer.
I have been stuck at 180lbs forever and have recently rearranged my entire life so I can wake up, eat, train, eat again and then go to work. So far it's been great. I plan to post pics just as soon as I hit 220lbs, which at this rate will be very soon.
Also, in terms of progress, you cannot measure it simply by looks. For all you know the 150lb trainers at your gym can pull a triple bodyweight deadlift. It's highly unlikely obviously, but for every trainer that is jacked there are fifty that aren't and don't want to be. It's all about goals. Now I do know trainers that talk about getting huge and ripped but don't know the first thing about bodybuilding so yeah, those types are very annoying. I sympathize with you there.
But for the most part the personal trainers I work with are highly knowledgeable and are good trainers on the whole. Once again, I would not send a bodybuilder to train with any of them, but for regular average joe, the yeah sure. I think it is highly dependent on what gym you go to. The 24 Hour fitness and Bally's and such will of course not have very good trainers. I mean, it's not impossible to find great trainers at those sorts of gyms, but they would be the exception, not the rule.