If it's getting that hot then you'll never get a motor or battery to last. I haven't looked at one of those planes, but if there isn't an exit at least twice as big as the intake for cooling air then you aren't going to get much flow. It would be a good idea to connect a watt meter to see how many amps you're actually pulling too. You are right, it shouldn't be marketed if it can't stand up to running wide open all day long (IMO, anyway). But sometimes their is a problem and ultimately it's up to the end user to catch it before it causes a crash or equipment damage.