Leave it alone until something breaks!*
*I mean, maintain it, lube everything thoroughly and don't just wontonly replace stuff.
Honestly, I'm sure it's a great bike for day to day use. If you're not satisfied with the braking, upgrade the wheels. It might even be worth your while to source out some aluminum hoops and build your own wheels using your stock hubs...
Note: My daily rider is a stock Schwinn Continental. I know from bad brakes! Heavy rain sucks on steel
rims, even if they are pretty comfy and adequate the rest of the time.