Issues remapping on controller

Why is it so much of a pain to remap certain actions on controller?
Like I found it strange that the default button layout is the cod-like “zoom and shoot” as apposed to the Halo 3 recon like before. Whatever, I play fishstick anyway, but why have the grenades on the left bumper and equipment on the right as apposed to it being the other way around before? Whatever, that’s a quick switch anyway, but why is it when I switch that over under “vehicle”, that unbinds my ascend when they literally don’t overlap? Unless you’re expecting people to be throwing grenades while piloting a wasp or something, but let’s not give anyone any crazy ideas.
And that’s just part of it. Trying to rearrange my grenades and equipment on the d pad in a way I’m comfortable with, I map an equipment to the left and it unbinds my switch grenades. That apparently is enough to throw off some delicate balance in the menu that you can’t get everything working on the d pad so you have to throw something on some other button. Maybe some people are comfortable something like that, but to fix that, I’d have to reset to the defaults, having me go back and reset everything, including my inverts and sensitivities.

When i used a controller i went with the classic halo 3 controls problem was legacy isn’t even like that…