Josh, dark suits today is an adopted frum levush as Jews have adopted there own levushim throughout centuries to distinguish themselves from the goyim. Let’s not go into whether you have to do that or not. The point is that those boys who do wear these suits and hats should be proud about it.
You know what, maybe with a change of levush comes expectation of more maturity and responsibilty which could very well be that those who do dress casually without a suit and hat don’t feel the change.
In any case, I think it’s important to let the boys know that the fact they are are going to HAVE to fulfill all the mitzvos that they will do is cause for celebration.
About bas mitzvas, okay, so maybe it’s NOT ONLY because of girls not performing more new mitzvos from one day to the next. But it is also not tzniusdig that girls should be focus and center of attention. I understand that Wolf brought a wedding celebration as an example against this reasoning. However, a bas mitzva is completely different than a wedding. Obviously, a bas mitzva girl will not be on the other side of the mechitza as her male guests would be by her chasunah. By a chasuna men and boys are busy being mesamiach chusan (hopefully), not her.
Anyway, the bottom line is, my husband and I will do as our minhug is (and I think a bar mitzva was a minhug in ALL of klal Yisroel, except today where it might become extinct in certain communities because “what’s the point” ) and make beautiful bar mitzvahs for my sons, iy”H. By beautiful I don’t mean lavish or showy, but rather a modest SIMCHA, an expression of thanks to the RS”O and excitement of our sons “coming of age”. And no our girls will not be jealous. They have no such hasugos of such “equality”. They will be excited as well for this SIMCHA.