@leemaze - So it appears you have not bi-wired at present, and I am assuming you are using the little jumpers that come with bi-wire speakers?
Get rid of the jumpers and replace them with copper wire jumpers - make each jumper about 20" long.
The jumpers that come with the speakers can be made from other metals but not copper - which accounts for the differences you are observing
You can even try Romex to start with - just to see if it improves things.
Use either 14 or 12 gauge wire.
If that works you can improve things even more by using a double strand of wire for each jumper and upgrade to UP-OCC copper wire
UP-OCC copper is superior to pure copper and even OFC copper.
You should be able to achieve a nice balance of the two improvements you mention but without moving the cables from one set of terminals to the other and without the expense of bi-wire cables
I actually tried bi-wire cables and changed back to the UP-OCC copper wire jumpers because of improved clarity and image achieved with a single cable.
The money I would have spent on a bi-wire cable I invested in better "normal" speaker cables.
Hope that helps - Steve