Even if you have no car yourself, maybe you have noticed that many cars have only 4 wheels although there are some with 6, 8 or even "infinity" wheels (e.g. chain drive continuous tracks on tanks). More isn't allways better, somtimes the scope of application says what is best.
My main problem with "Big Stack" is, that almost every calculator cooks its own soup here and there is no standard for stack handling (error-to few arguments, LastX vs undo etc.) and delete/drop. On the big stack road there was no progress to find the best way to handle, even HP28 & HP48 does it different (e.g. backspace with empty stack gives an error on 48/49/50 but not on 28, the prime returns to the 28 way, the DM42 does it like the 48).
I like the possibilities offered by RPL, like convert the stack to lists or matrix but in every day calculations I prefer classic RPN with the 4 level stack.