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.
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.
it should be shaped like a tooth as much as possible
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.