Forget changing wire, biwiring, or biamping.
Consider speaker placement, listener placement, room treatments, EQ, and speaker modifications or upgrade.
Pull your speakers away from the front wall another couple feet. How does it sound now?
Pull the speakers away from any nearby sidewalls a couple of feet. Thoughts?
If you are against the back wall, put some sliders on the couch feet, get away at least a few feet. Impressions?
Starting point for listener position in a closed rectangular room is 38% of the room length. Variation from room to room, but will be close to that.
Start with all of the above. Because it is all free.
You may consider trapping for bass, particularly at the corners, or meetings of boundaries. First reflection points are normally a good thing to absorb as well, if you're at it.
My HT speakers are also not extremely transparent when it comes to midbass, and I guess that this is attributed to cabinet resonance to some extent. Also, my center speaker is too close to floor, which will create large midbass boosts that in turn mask dialogue frequencies. I have significantly treated my room, then applied Audyssey MultEQ XT to very beneficial effect, IMO.
If Chris or Andrew are remotely familiar with your speakers, they may have recommendations on speaker mods. If they were willing, had the time, thought it was even worthwhile, and you have money, you might be able to send your speakers to them for mods that you are unwilling to do yourself.
Or you can upgrade speakers.