Temporarily disconnect the Sizmik.
If the sound is still out of balance, it would seem to be a reflection issue between the Katans and the left wall. If so, and you can't move the speakers because of "the look", then you can try what Newbee suggested. You could also investigate the option of an acoustical treatment to absorb some frequencies at the reflection point. If an acoustical panel doesn't satisfy "the look", perhaps some artful object chosen by your wife. How about a small tapestry or a velvet painting of Elvis?
On the other hand, if removing the Sizmik causes the balance to be restored, then it is a subwoofer issue. It is quite possible that having the sub in the corner is reinforcing the bass freqeuncies on that side of the room and directing it towards you like a horn. If that is the case, room treatments are likely to be impractical since you would need large bass traps. Another alternative is to adjust the sub's crossover a bit lower. This may eliminate the offending frequency. However, your ability to do this will be restricted by how well it integrates with the Katans. Another option is to replace the Katan/Sizmik with a fullrange floorstanding speaker. That gets rid of the sub in the corner and frees up space which your wife will appreciate. The footprint will be the same as for the current Katan/stand and a good speaker choice will look just as good. In fact, if you like Linn, how about this....sell the Katan/stand/Sizmik and replace with Ninkas. Same look. Same footprint minus the sub. Better performance. You will make money on the sale and purchase, the profit of which you can lavish on your wonderful wife...for future considerations. How devious! Or you could keep the profit and invest it in an even better pair of floorstanding speakers.
Another possibility is that you have a hearing impairment in one ear relative to the other and this is showing up as a channel imbalance.