Heck, nearly everything in a bathroom can be improved: faucets (re-adjust every time you use them, run water until desired temperature is reached); sinks (too shallow to do anything in, faucet gets in the way); medicine cabinet (reach over sink, too shallow so stuff falls out, fingerprints on the glass every time); toilet (cold, too low, smelly, spray goes everywhere, noisy); shower (curtain useless, water leaks out, run wasted water until warm, can't spray water UP at all, crowded for two or more) and so on.

Spider Robinson had a character in the Callahan's Saloon series that went into some detail on this.

Bathrooms usually have fans that vent outside to take care of moisture. All new homes have ventilation that replaces the air at least twice an hour. This is not to say that it couldn't be better addressed, but these issues have not gone unnoticed.