Am a long-time stereo enthusiast (and likewise big waster of $$), also know well a high exec at HK. HK is a shadow of its former self, they've staked their prior well-earned reputation to become a shameless volume seller, and their new stuff is run of the mill crap, including the receivers. The exec confirms what I experience firsthand.
That said, you can never expect a non-luxury marque to have a decent stereo, even an "upgrade stereo". The marketing of Bose, HK, AR, etc. is just marketing and a production contract arrangement. For the masses, the HK should do just fine. However, if you have an inkling that it doesn't sound great, it's because that's the truth.
You will still fly high by swapping for after-market components, even modest ones. Always start with the tweeters and end at the head unit.
Also, we own a 2012 Limited (Legacy) and a 2015 OB Limited. The 2012 system sounds better IMHO, although that could be sedan over wagon effects. But both are muddy and have too many peaks and valleys, difficult to correct with the EQ.
My aftermarket HU on my Honda saves EQ settings for each Source, have not checked if the 2015 HK does this, but its very necessary given the disparities between CD, XM, Pandora, BT Audio MP3, etc. It also has multiple speed-sensitive adjustments (rather than just one) that make a big difference (Honda has a lot of road noise for one).