Were some custom moves (or at least the elements of some moves) meant to be the original?

[Dardo]

I was playing around with some customs and I noticed that some characters have great variety in terms of customs like Megaman/Palutena or have customs that barely change them for better or worse (like Captain Falcon). In fact some characters are downright better by switching all of their moves to a custom version (Olimar oh my goodness Olimar). Customs were meant to be a good alternative to a move and not a complete replacement, or at least, not have small elements that could have been included as one move/custom. For example, Pit's Side B has a custom called the Interception Arm, in which Pit stays stationary with his Upperdash Arm and strikes only if an opponent is nearby.

My question is, why was this split into two different moves?

Why not keep the ability for Pit to stay stationary and have it be like a temporary charge attack? You can just hold down B to keep the move stationary and let go to attack, or else it will stop and fail (similar to what Luigi's Green Missile has now). Or just quick tap it to make it behave normally and attack.

Even better Ike's B, Eruption. Why not combine that with Furious Eruption's elements? Make Eruption powerful, but with damage recoil like Charizard's Side B?

I can go on and on about examples of how move's elements were split apart to be one separate custom move just so they can fill up all 3 slots. But I think I made my point clear. I think it's absurd that this possibly happened or that they spent to much time making Lucina and Dark Pit separate characters.

*walks away from mic*

*shouts from a distance* AND WHY CAN'T PIT'S UP B JUST HAVE THE STRIKING FLIGHT'S ATTACK WITH THE PRESENT UP-B ALREADY!? LUCARIO HAS IT WHY CAN'T PIT?!?!?!?!?!