Lack of hot water is a clear sign that there are some serious problems with the water heater and that the water heater needs to be fixed as soon as possible.
Some people can ignore this, but they shouldn't. If you think the heater is not heating enough water, you should have it repaired as it may not produce hot water in the future
Drips or splashes of water from the water heater or even rust or white deposits should not be avoided, this could be a serious problem and should be fixed as soon as possible.
The foul odor originates from bacteria growing on the sediment inside the tank. Drain and clean the tank as soon as it smells bad.
Sounds like loud pops are unusual and can cause them to break down and turn into the sediment. If you hear an unusual noise, have it checked by a plumber as it could be dangerous