If Yamaha makes a 76 key arranger with weighted graded hammer action, then that defeats the purpose of making a 76 key arranger. At that point, you might as well make it 88 keys.

The purpose of 76 keys is to strike a compromising balance between the player who plays synths and organ sounds but need some extra keys to play piano and e-piano parts.
If they are making a weighted graded hammer action board, that shows that they are only making it for a piano player and should make it 88 keys.

O and here is the other problem if Yamaha makes a 76 weighted graded hammer action arranger. When it does not sell, then Yamaha would say: “See, a 76 key arranger does not sell”. Of course it would not. You made it wrong by making it weighted graded hammer action. No all purpose keyboard player who plays organ/synth sounds 60% of the time and piano sounds 40% of the times would by that. The only persons who would buy such a keyboard would be those who would want to play piano style 95% of the time. At that point, you would be better off making it 88 keys.