Going with the blue background and white letters led them to use the complimentary Orange against the background to make anything they wanted to stand out do so.
So the question becomes to me what is it that you and sam want the arrow to do. stand back in the background as a reminder or is it to be a more obvious marker to the player to another screen. there are merits to both. As you want the player to be able to find it, but you also don't need attention called to every time after they know it's there.
I'm going to lean towards the Orange based both on its location on the screen and the fact that it donates an action the player can take. and it just feels more intuitive to the design, almost like I don't have to think about it being an arrow, in the same way, you don't think hey there is a stop sign you just instantly stop. that being said I find the white also appropriate and could be swayed perhaps to change my stance.
I think that's an excellent summary of the situation and the choices!

I think it should be white because it's just a little hint that there's more to the menu. You can play the entire game and never need to access the inventory, so a glaring orange billboard seems a bit much.
And this is basically the argument for using the white arrow.
It's the smallest change that we can make that *might* give the player a clue that there's more to see if they press right on the joypad when they're at the edge of that part of the menu.
In that case, while I like the look of the white arrow better, I'd say go for the orange one because, as it was said by more than one people before, it can't be missed, but not only that, there's already another orange arrow elsewhere on the screen, having this particular arrow also be orange would make the UI look more consistent you know what I mean?
And this is the argument for using the orange arrow.
Falcom are using the color white for "status/information/deselected", and orange for "current-selection/selected/press-this".
They are already using the same orange arrow on the switch that changes between the ICON and CFG buttons (i.e. the menu changes when you press that button).
So an orange arrow already has a defined meaning in Falcom's UI design, and putting another orange arrow on the border is consistent usage.
A white arrow is never used anywhere else in the game to signify anything. It has no defined meaning. But perhaps you could consider the white "deselected" buttons as giving enough of a clue.
I do understand the idea of making the smallest *visible* change in order to give the player a clue, especially when, as Necromancer says, you can play through the whole game without ever going to the Inventory screen.
The problem is (from my POV), that a white arrow is actually a *bigger* change to Falcom's UI, because it has no meaning, and doesn't fit in with their design scheme, wheras the orange arrow looks like it could have been a part of the original screen.
At the end of the day, I don't think that it really matters which color we use; but I strongly favor consistency in meaning and operation, and so lean towards the orange arrow. It's just (IMHO) clearer what it means.
And now that I've said that ... the white arrow is what is currently implemented in the game!
