I think you are correct that a crown should have the anatomy of a natural tooth. It sounds like there was insufficient tooth structure removed from the prepped tooth to allow for a more anatomic shaped crown.
it should be shaped like a tooth as much as possible
if it's flat it is becasue the tooth was not prepared enough, or the tooth is very short (which is common on #15) and thedentist did not want to drill it down anymore. I usually try to do #15 in gold with no porcelain. it can't break, and there is more bulk in which to carve tooth anatomy. no one can see it anyway.
If the tooth is left as is, will it cause any problems. It is slightly annoying but I think I will get used to it. However, if it is going to cause problems (ie. unusual wear on the lower teeth), I would want to have it fixed.