Once it starts raining hard enough and/or your speed gets high enough wet lower legs and feet are a certainty. I'm sure someone will come along shortly and tell me I'm wrong and it's easy to have toasty dry feet in a torrential downpour.

Anyway, the biggest thing for me is keep my feet warm. They can get as wet as they want as long as they stay warm. I use mylar sheeting under shoe covers (because it's cheap) to keep out the wind as well as insulated insoles to help retain the heat generated by pedaling. Once the zippers on my shoe covers fail I may try some Velotoze as they look like a more complete and thus warmer coverage.

Oh obviously I run fenders, I've used them almost always. Even some like raceblades make a big difference but these days I ride full coverage fenders and they work well for keeping most of the spray down. My feet usually only get wet due to the v-shaped spray that comes off the tire when riding through puddles at speed. Nothing to do to prevent that.