My grandparents got an RL this past spring. They chose it because it's comfy, has inoffensive styling and the lease was reasonable. They don't care about driving in the snow (and I haven't ever seen the RL marketed for its snow capabilities...) because they go to Florida for the winter. They don't care if it's rear wheel drive or if it's got decent power or anything like that.
Now if Acura is content to keep selling to this kind of buyer, they can come out with a similar car. If they want to get people to think the RL is worth cross-shopping with the likes of the 540i, E500 and GS430 they're gonna have to do something exotic with both the powertrain and the styling. Yeah a 3.5-liter i-VTEC V6 would have no problem matching the peak output of the competitors' V8 options, but it wouldn't have the sort of grunt down low or the light steering of a RWD V8 car. Now if the base model were offered with like a 260 hp 3.5-liter V6 (to provide the necessary low-end torque for this class) and an RL-S had the AWD hybrid deal goin on that could work well. I guess if Honda won't build a RWD V8 car it's the next best thing.