I feel ignorant... I don't know what a noun phrase is. Ok, wait, checking on Wikipedia in progress... found! -->
[link]If noun phrases are like those, then I don't think they are much of a problem. But it depends on what you really mean... because I think I might agree on the fact certain structures with complex noun phrases are not emphasized while teaching English at all. For example:
Jenny's cat is the biggest I have ever seen. <--- All grammar books are full of these examples.
Jenny's boyfriend's cat is the biggest I have ever seen. <--- Never seen anything like this.
Bob and Mary's house is in Denver. <--- All grammar books cover this.
Me and my partner's house is in Denver. My partner and I's house is in Denver. <--- Never heard anyone trying to explain anything like this, where pronouns are involved.
Is that what you mean? If so, I also have to say there are a lot of other areas that are not emphasized by teachers. A widely neglected one is "weak forms", in my opinion... much, much more than noun phrases.
Just my thoughts...