I wouldn't think so. palette RAM is 512 bytes, at 15 bits per entry.

As far as stuff broken on 8bpp, though, the palette bits in the tilemap do have a use. you can turn the palette selection and palette-ized color into a direct color mode. If I knew what was broken, I could cross-reference with some of my "known places that use this feature" lists and see. (Actraiser II for Direct Color)