Several great suggestions from many.
Keep RE4 style gameplay. But maybe with the power of PS3, combine guncon2, dance pad, and eyetoy to produce a virtual RE5 seen through first-person.
Include third-person option, with multiple character choices and radically different paths. Example: Jill, Chris, Ada, and Claire.
Co-op on LAN.
Jill should be a Sienna Guillory scan with destructible zombie-damageable clothes.
Oh, and default with 2 attache cases from the start.