This nails it. There is a clear lack of refinement and, more importantly, a lack of craftsmanship in these beers that bothers me. What I don't get is that there are plenty of sub-5% ABV hoppy beers out there that don't lack the mouthfeel I correlate with a well-made beer. Clearly there is a difference between APA and Session IPA, and the difference to me seems to boil down to something that is well made (designed "bottom up" as you say), and something that is merely a brewer cramming hops into a lower alcohol beer without any attention being paid to anything other than the hop flavor. Given the wide variety of APAs out there, these seem not only redundant, but a worse version of a beer style readily available in the marketplace, that is selling well due to better marketing. You can put 80 or 90 IBUs of hops into a 4.5% ABV beer and not have be watery and lacking mouthfeel. Brewers are just choosing not to, for the most part.