It's true. That's kind of part of it though. Nintendo has said that Luigi is more powerful than Mario, and Al is totally better at alchemy than Ed... Ed just has the advantage of having crossed over to the other side. Basically, they're both way better, but they get overshadowed by their louder/more popular brothers.
Well, both Al and Ed are now living Transmutation Circles (I theorize that it happens when your entire body becomes a part of any transmutation in any point in your life), so they are equal in that respect, but I see what you are saying. Jumping is everything in the Mario universe, and Luigi has the highest jump out of all of them (of course Peach can float).
About the whole overshadow thing - It's like H.G Wells. The fabled author was just a mustache, who's name wasn't actually H.G Wells, and he is actually a she. It's too bad she went crazy :/.