I say - each to their own...We have Boy-Girl twins so they cant be dressed exactly the same as such...
I like to have them dressed similarly - If hayden has short and a T-shirt so does Brooklen just in a girls style etc...If Brooklen is wearing a Dress Hayden certainly doesnt and he wears something different

When they were tiny babies, we dressed them in yellow ,white and green everything and most of the time it was easier to get out two jumpsuits IYKWIM

I am sure kids will let us know what they want as they get older - until then its a Parents choice...They can only look back on pics and tell us off when they are older LOL