There is a big difference between a pram type dinghy which is very efficient for carrying a load in a short length and a sailing type dinghy which is designed to plane. Any cruising boat will exceed the "hull speed" of a dinghy. A pram will not plane readily so it stands up and creates a lot of drag. A sailing dinghy that is designed to plane easily will cause a lot less drag. Beware with a following sea though since they are more likely to surf right past you or even crash into the stern.

Towing a dinghy can cause trouble in some conditions but may be the best solution. If it swamps in storm conditions you may have to cut it loose. But most of the time it is not really a problem. If it's designed with sufficient flotation, it may become a lifesaver. Like many other cruising things, just deal with it.