Indeed. What the hell happened after SotN? Why did it become necessary to outline everything and make everything bright? I can understand compensating for the original GBA not having a backlight, but DoS and PoR have no excuse whatsoever. SotN has visuals that, although 2D, look somewhat realistic and convincing. DoS and PoR both look animated through and through, for reasons I'll never understand. The PSP DXC shows that it's not necessary to have bright visuals on a handheld CV. And the DS can easily handle SotN-style visuals, even if they aren't the same resolution.
Platforming and level design also took a huge nosedive after SotN. It seems like the people who were actually responsible for the Wonder that is SotN are no longer with the CV team, and Iga ended up with all the credit for some unknown reason.