Hmm now that I consider it, it COULD be Yoshi. Again, just COULD. His Egg Throw is good enough to be described with 'Great Long Range Game'. I mean, you could basically hit anywhere with them, and they aren't too slow. He does have a surprising ability to KO, like (or may be just mostly) his upair. I don't know about the 'lots of potential part' though, as there are many Yoshi Haters out there. But those who did like Yoshi or did see that he does not suck as much as some think so, those did see a lot of potential in him. I don't know about the 'very few faults' part, as I don't see too clear of a definition for 'fault'. His recovery is wierder I guess, but I wouldn't call it a fault. The only fault I can think of, is slow Rolling Dodge. I guess you could say that he has a lot of faults though, just for being a character not of a Higher Tier. IMO he is about the same or better against DeDeDe than those most people list, like Fox, Lucas, Olimar, Toon Link (these I got from SHOK's opinion). DeDeDe can usually just play defensively by perfect shielding/ shielding attacks then grabbing them, and can use Waddle Dees to counter projectiles. But Yoshi gives me a hard time. His Egg Throw is annoying, since I can't use my Dees as a sheild, and throwing them up in the air at the eggs is a bit hard and the Dees are slower than the eggs. You can't just shield grab them when they come by, since Yoshi will usually approach with a bair, which hits very hard on his shield and usually hits him out of it. His Bair is fast too, so it's hard to use an attack to hit him first. Fair usually doesn't work, since Yoshi can jump over it. Yoshi's Bair has quite a lot of priority, or at least against DeDeDe. It has nice range too, so trying to use a Bair to counter Yoshi's Bair is a bit hard also.
He hasn't been doing THAT well in tournys (yes, many when you read this you will probably think something like: well, no duh! he sucks in tournys!, but he does do good in some tournys, or at least in Online Tournys, but I guess Onlines don't count

), despite Yoshi users loving his new buffs and seeing his potential.
I just thought of Yoshi when I was thinking of those that give my DeDeDe a hard time. Fox, Toon Link, Olimar, and Lucas may give a hard time, but I can still manage to get through the disadvantages. I feel that Yoshi is a lot more dangerous often times to me.