Having played as mostly yoshi for the past few days and having had wifi experience against melee pros in a crew, I'd like to say that your yoshi ratings are flawed. I am not going to write an essay or anything of the sort right now, as I'm rather tired and want to sleep, but as yoshibomber said earlier, check out the yoshi brawl forums. I've written at least a page's worth of stuff there on the subject of his changes, scattered across a few threads. I'll understand if you don't want to go over there, but the greater part of my work is there. I'll probably post more here tomorrow to back my statement.
For now I'll just give a couple brief points. First off, Yoshi's b-up is not limited to two consecutive uses. In fact, I've regularly used it three or four times. Admittedly, it does wear greatly by the fourth time, but by that point, all I need is a little bit of horizontal movement, anyway. With some skill, you can ward any would-be edgeguarders away with those eggs during your recovery, allowing for a safe landing.
Secondly, I see no reason for you to say that all, most, or even half of his moves have been nerfed. In my experience, other than his lack of DJC (more on that later,) most of his moves have been buffed. This is particularly evident in his aerials and tail-using attacks. His tail has become a decent amoung longer, giving him reach that often makes the difference in close match-ups. His f-tilt is a completely different attack, one that has more range and combo ability (f-tilt to f-tilt to upsmash works wonders on low damages.) His yoshi bomb now hits on the way up, serving as a decent intercept for would-be aerial attackers, and stopping them just enough so that they almost always will be hit by the decent, guaranteeing some decent damage and knock-up. His boot also gets bigger in his nair than in melee, and has simillar properties. His grabbing range has increased slightly, and due to the lack of l-cancelling, shield grabbing is more of an option now. Despite the floatiness of the game, I've still been able to use the down-throw to combo effectively. His f-smash has lost a small amount of range, but it still has decent range, and very nice power.
I will agree with you on the issue of his double jump super armor, though. It's lost a good amount of it's charm. Though with its increased speed, his b-up recovery, and auto edge grabbing, this is somewhat less of an issue. The lack of DJC is his biggest drawback in brawl, I'm still experimenting with that, He still has a quicker edgehog than everyone else's auto edge-grab by a little bit, though.
Other than the yoshi section, I did enjoy your analysis, good job. =) I hope I don't come across as attacking you or anything, just putting my playing experience out there for review.