How's this for a story?

A long time ago, somebody found a baby boy at the door of their house. That boy turns out to be the king's son and goes and fights for good, for truth, and for all of that other stuff!!!

Would that make a good story?

You would have to put a whole bunch more plot in there to make it work. That by itself has been done tons, so you can't rely on it at all to get readers or publishers.

But can be made to work if you do it right.

I agree, that sounds a little cliche, and the only way around using such a cliche is to throw a twist we haven't seen. Like, what if the person whose door he lands on is the king's enemy? What if that door led to another dimension and he has to find his way back before the person who sent him there takes over his father's kingdom (that may be cliche also).

Discover your character's desires and weaknesses and the lesson God has for them, and you can overcome any cliche, as long as they are strong enough to overshadow the cliche.