My wheels came standard with these odd sort of rubber seal that was part of the bearing cone, it worked and still works great, a double lip kind of edges in the hub that mesh nicely and keep out stuff.
I can only see 2 problems with a standard radial bearing in a bicycle wheel, that the bearing doesn't take side loads as well as the angle contact bearings that are normally seen in wheels, and that the bearing cone is designed to be threaded on the axle, which means absolutely no play from the inner race on the axle, a hardened radial bearing race on the axle on the threads can eventually roll and flatten the threads, which will give vertical play, and the more play the worse it wears making more play. I simply couldn't ride on that without worrying about my bearings bursting at the seams.
I failed a lot of bearings in bikes, vehicles, and roller skates. I found that sometimes it really just takes only the right bearing to get the job done, and since I only have 2 bearings keeping my wheel from dismantling itself in the middle of a ride on a road with big metal things that kill squishy people bodies I'm going to just get the right bearing on that the first time and use the right grease of course to keep them rolling smooth.
I question why your hub side race cracked. Doesn't happen often, rarely in fact, are you sure the hub isn't warped or cracked, leading to a place for the bearing to breach without proper back support.