Does bewiring decrease "wholeness" ?

I never noticed this when bi-wiring nor do I with my current bi-amp setup.

Sounds like the sales guy doesn't know what he's talking about. Seek a second opinion, as everything I have ever read and experienced is contrary to what you were advised.

Are you sure the sales guy was talking about bi-wiring, no bi-amping?

Bi-wiring is a personal preference and system dependent. Not just speaker dependent.

In my experience, a better mono-wire has provided better overall sonics over lesser bi-wire where both versions cost about the same.

Remember that you are paying for the extra wiring and terminations. Sometimes you can get substantially better quality mono-wires for the same price.

Lastly, one should not feel that they must bi-wire simply because a salesperson or mfg'er suggests they do. Not saying that's why you are, but I just thought I'd mention it.

-IMO

Herewith this modest proposal: Get a friend and a blindfold and try them both ways, without your knowing which way is which, with a cd you've heard at least a hundred times. Can you hear a difference? If so,wire them the more desirable way.